In the January 5, 1951, episode of Edward R. Murrow's Hear It Now radio broadcast, Atomic Energy Commissioner Gordon Deane fields questions from reporters about Russia's possession of the atomic bomb.
Russia declassifies footage of 'Tsar Bomba' — the most powerful nuclear bomb in history
The blast was more powerful than 50 million tons of TNT, and was felt hundreds of miles away.
In October 1961, the Soviet Union dropped the most powerful nuclear bomb in history over a remote island north of the Arctic Circle.
Though the bomb detonated nearly 2.5 miles (4 kilometers) above ground, the resulting shockwave stripped the island as bare and flat as a skating rink. Onlookers saw the flash more than 600 miles (965 km) away, and felt its incredible heat within 160 miles (250 km) of Ground Zero. The bomb's gargantuan mushroom cloud climbed to just below the edge of space.
This was RDS-220 — also known as the Tsar Bomba. Nearly 60 years after the bomb's record-shattering detonation, no single explosive device has come close to matching its destructive power. Last week, Rosatom State Atomic Energy Corporation (Russia's state atomic agency) released 40 minutes of previously classified footage, showing the bomb's journey from manufactor to mushroom cloud. Now, you can watch it all on YouTube. (The countdown to detonation begins at 22:20).
Soviet Premier Nikita Khrushchev personally commissioned the construction of the Tsar Bomba in July 1961, Popular Mechanics reported. While Krushchev wanted a 100-megaton nuclear weapon, engineers ultimately presented him with a 50-megaton version — equivalent to 50 million tons (45 million metric tons) of TNT detonated at once. Even with half of the premier's requested payload, the bomb was unfathomably powerful. The bomb was thousands of times stronger than the nukes detonated by the United States over Hiroshima and Nagasaki during World War II, and dwarfed the detonation of Castle Bravo — the most powerful nuclear weapon ever tested by the United States — which yielded just 15 megatons (13 million metric tons).
As the new footage shows, the Tsar Bomba was enormous, weighing 27 tons (24 metric tons) and measuring about as long as a double-decker bus. An aerial bomber carried the massive weapon high over the Novaya Zemlya islands in the Russian Arctic, then dropped it via parachute before clearing the area. The explosion was so powerful that it actually knocked the aircraft out of the sky, causing the plane to plummet 3,000 feet (900 m) before the pilot could right it, according to Popular Mechanics.
Thankfully, no human casualties have been attributed to the Tsar Bomba detonation, and no bomb matching its power was ever tested again. In 1963, the United States, the Union of Soviet Socialist Republics (USSR) and the United Kingdom signed the Limited Nuclear Test Ban Treaty, which prohibited airborne nuclear weapons tests.
Since then, atomic tests have carried on underground as nations continue to stockpile nuclear weapons, occasionally changing the geography of the Earth around them. One 2018 nuclear test conducted in North Korea caused an entire mountain to collapse over the test facility — a reminder, perhaps, that the world hardly needs another Tsar Bomba in order to wreak devastating nuclear damage.
Originally published on Live Science.
It should be pointed out that many experts in the field of strategic nuclear weapons, and their potential use, will describe an effective ABM system as more of a destabilizing effort than an applicable one. It is seen by most adversaries as a true defense, and not simply as a deterrent, providing the potential for a first strike capability. One must think with their heads, not ours, to consider their responses to such a deployment.
As the tech war heats up, it would be prudent to negotiate a new ABM treaty banning interception of long-range delivery systems dedicated to nuclear warheads. The ability to overcome them with decoys, or increasing the number of missiles renders their effectiveness questionable in real terms, but perhaps not to those who might push the buttons. If your enemy thinks they are vulnerable, they will take additional measures to counteract such a threat and do something about it. Doubtless the Russians and Chinese, with their expertise in space technology, would not have a problem counteracting such interception systems, using the above methods.
North Korea, on the other hand, is in no position to ramp up their threat capability. Kim et al. surely must know that if they launched a preemptive attack on us, or any of our allies, we would be bouncing their rubble a dozen times over, just to be sure. Kim's greatest threat seems to be his rhetoric, not his nuclear stockpile. He certainly cannot be considering vaporization as a result of any future "defense" plans.
Because the fireball had not made contact with the Earth, there was a surprisingly low amount of radiation
Such a blast could not be kept secret. The US had a spyplane only tens of kilometres from the blast. It carried a special optical device called a bhangmeter useful for calculating the yield of far-off nuclear explosions. Data from this aircraft – codenamed Speedlight – was used by the Foreign Weapons Evaluation Panel to calculate this mystery test’s yield.
International condemnation soon followed, not only from the US and Britain, but from some of the USSR’s Scandinavian neighbours such as Sweden. The only silver lining in this mushroom cloud was that because the fireball had not made contact with the Earth, there was a surprisingly low amount of radiation.
It could have been very different. But for a change in its design to rein in some of the power it could unleash, Tsar Bomba was supposed to have been twice as powerful.
One of the architects of this formidable device was a Soviet physicist called Andrei Sakharov – a man who would later become world famous for his attempts to rid the world of the very weapons he had helped create. He was a veteran of the Soviet atomic bomb programme from the very beginning, and had been part of the team that had built some of the USSR’s earliest atom bombs.
Sakharov began work on a layered fission-fusion-fission device, a bomb that would create further energy from the nuclear processes in its core. This involved wrapping deuterium – a stable isotope of hydrogen – with a layer of unenriched uranium. The uranium would capture neutrons from the igniting deuterium and would itself start to react. Sakharov called it the sloika, or layered cake. This breakthrough allowed the USSR to build its first hydrogen bomb, a device much more powerful than the atomic bombs of only a few years before.
Sakharov had been told by Khrushchev to come up with a bomb that was more powerful than anything else tested so far.
The Tsar Bomba was carried to the drop zone by a modified version of the Tu-95 𧯪r' bomber (Credit: Alamy)
The Soviet Union needed to show that it could pull ahead of the US in the nuclear arms race, according to Philip Coyle, the former head of US nuclear weapons testing under President Bill Clinton, who spent 30 years helping design and test atomic weapons. “The US had been very far ahead because of the work it had done to prepare the bombs for Hiroshima and Nagasaki. And then it did a large number of tests in the atmosphere before the Russians even did one.
“We were ahead and the Soviets were trying to do something to tell the world that they were to be reckoned with. Tsar Bomba was primarily designed to cause the world to sit up and take notice of the Soviet Union as an equal,” says Coyle.
The original design – a three layered bomb, with uranium layers separating each stage – would have had a yield of 100 megatons – 3,000 times the size of the Hiroshima and Nagasaki bombs. The Soviets had already tested large devices in the atmosphere, equivalent to several megatons, but this would have been far, far bigger. Some scientists began to believe it was too big.
With such immense power, there would be no guarantee that the giant bomb wouldn’t swamp the north of the USSR with a vast cloud of radioactive fallout.
SEE IT: Russia releases 59-year-old video of most intense bomb blast in Earth’s history
For the first time in nearly 60 years, Russian energy corporation Rosatom has released video of the most powerful nuclear bomb ever to be detonated on Earth, reported IFL Science.
The enthralling footage, which serves as Soviet Space Age propaganda, chronicles the creation and ultimate release of the Tsar Bomba — literally the “King of Bombs” — a massive hydrogen explosive tested in 1961.
The absorbing, 40-minute documentary — in Russian with English subtitles — details some of the engineering and design work that went into the bomb’s creation before leading up to the critical crescendo of the explosive’s daunting detonation.
Why Russia Built A Bomb 3,000 Times Deadlier Than What America Dropped On Hiroshima
Here's What You Need To Remember: The Tsar Bomba was so big, it’s doubtful whether it could ever have been a practical weapon delivered by a Soviet bomber. Because of the distance from the Soviet Union to America, removal of the fuselage fuel tanks to accommodate the bomb — combined with its sheer weight — meant that a Bear bomber wouldn’t have sufficient fuel for the mission even with aerial refueling.
Maj. Andrei Durnovtsev, a Soviet air force pilot and commander of a Tu-95 Bear bomber, holds a dubious honor in the history of the Cold War.
Durnovtsev flew the aircraft that dropped the most powerful nuclear bomb ever. It had an explosive force of 50 megatons, or more than 3,000 times more powerful than the Hiroshima weapon.
Over the years, historians identified many names for the test bomb.
Andrei Sakharov, one of the physicists who helped design it, simply called it “the Big Bomb.” Soviet Premier Nikita Khrushchev called it “Kuzka’s mother,” a reference to an old Russian saying that means you are about to teach someone a harsh, unforgettable lesson.
The Central Intelligence Agency blandly dubbed the test “Joe 111.” But a more popular name born out of Russian pride and a sheer awe sums it all up — the Tsar Bomba, or “the King of Bombs.”
“As far as I can tell the term did not surface until after the end of the Cold War,” Alex Wellerstein, a historian at the Stevens Institute of Technology and blogger, told War Is Boring. “Before that it was just called the 50 megaton or 100 megaton bomb.”
“I think we make a lot more of the Tsar Bomba today than anytime other than the immediate period in which it was tested.”
“Americans like to point to it as an example of how crazy the Cold War was, and how crazy the Russians are and were,” Wellerstein added. “Russians seem to take pride in it.”
On Oct. 30, 1961, Durnovtsev and his crew took off from an airfield on the Kola Peninsula and headed to the Soviet nuclear test area above the Arctic Circle at Mityushikha Bay, located in the Novaya Zemlya archipelago.
The test project’s scientists painted the Bear bomber and its Tu-16 Badger chase plane white to limit heat damage from the bomb’s thermal pulse. That’s at least what the scientists hoped the paint would do.
The bomb also had a parachute to slow its drop, giving both planes time to fly around 30 miles away from ground zero before the nuke detonated. This gave Durnovtsev and his comrades a chance to escape.
When the planes reached their destination at the predetermined altitude of 34,000 feet, he ordered the bomb dropped. The chute opened, and the bomb started its three-minute descent to its detonation altitude two-and-a-half miles above the earth.
Durnovtsev pushed the throttles to the max.
The blast broke windows more than 500 miles away. Witnesses saw the flash through heavy cloud cover more than 600 miles from the blast site.
Its mushroom cloud boiled up into the atmosphere until it was 45 miles above ground zero — essentially, the lower boundaries of space. The top of the mushroom cloud spread out until it was 60 miles wide. The nuke’s thermal pulse burned the paint off of both planes.
And that was small compared to the Soviets’ original plan.
The designers originally intended the bomb to have a 100-megaton yield. They used a three-stage Teller-Ulam lithium dry-fuel configuration — similar to the thermonuclear device first demonstrated by the United States during the Castle Bravo shot.
Concerns about fallout prompted Russian scientists to use lead tampers that dialed down the yield to half of the bomb’s capabilities. Interestingly enough, Tsar Bomba was one of the “cleanest” nuclear weapons ever detonated, because the bomb’s design eliminated 97 percent of the possible fallout.
Even its size was monstrous. It was 26 feet long, about seven feet in diameter and weighed more than 60,000 pounds — so large it couldn’t even fit inside of the bomb bay of the modified Bear bomber used to drop it.
The Tsar Bomba was so big, it’s doubtful whether it could ever have been a practical weapon delivered by a Soviet bomber.
Because of the distance from the Soviet Union to America, removal of the fuselage fuel tanks to accommodate the bomb — combined with its sheer weight — meant that a Bear bomber wouldn’t have sufficient fuel for the mission even with aerial refueling.
However, the CIA investigated whether the Soviets planned to place similar warheads on super-powerful intercontinental ballistic missiles that would target American cities.
The reason was accuracy. Or rather, the lack thereof. Because of the NATO alliance’s nuclear advantages, the United States could place bombers and intermediate range ballistic missiles fairly close to Soviet targets in Eastern Europe.
By the late 1950s and early 1960s, America placed intermediate-range ballistic missiles such as the Thor in the United Kingdom and Turkey, and Honest John and Matador missiles in West Germany.
The shorter flight distance for those missiles meant they had a better chance of delivering their nuclear warheads effectively on target.
Russian nuclear weapons had further to travel, so there was more chance of missing the mark. But for a 100-megaton warhead … close enough will do.
Consider the damage a 100-megaton version of the Tsar Bomba could inflict on Los Angeles — say, if detonated directly above the U.S. Bank Tower, the second tallest building west of the Mississippi River.
On a clear day, an airburst at 14,000 feet above ground level would produce a nuclear fireball two miles wide that would be hotter than the surface of the sun, reducing concrete and steel skyscrapers to ashes.
Within five miles of ground zero, everyone not killed by the blast and heat would receive a lethal dose of 500 rems of high-energy radiation. Up to 20 miles away from the detonation, the blast wave would gut every building — even concrete and steel reinforced buildings.
Up to 50 miles away, anyone exposed to the flash of the weapon would receive third-degree burns. In short, a Tsar Bomba warhead would completely devastate the entire Los Angeles metropolitan area.
In 1963, Khrushchev said the Soviet Union possessed a 100-megaton bomb that it deployed to East Germany. But the premier’s claim has divided historians on whether it was true, or was just boasting.
As for Sakharov, his experience building and testing Tsar Bombachanged his life, prompting him to abandon weapons research.
He became an outspoken critic of Soviet efforts to create an anti-ballistic missile defense system, an advocate for civil rights in the Soviet Union and much-persecuted political dissident who won the Nobel Peace Prize in 1975.
And Durnovtsev? Immediately after successfully dropping Tsar Bomba, the Soviet air force promoted him to the rank of lieutenant colonel. In addition, he received the Hero of the Soviet Union award, the highest honor bestowed for service to the Soviet state.
What If Germany Had Developed the Atomic Bomb?
I n the Star Trek episode “The City on the Edge of Forever,” a temporarily insane Doctor McCoy passes through a time portal. The landing party sent to retrieve him discovers that it has lost contact with the orbiting starship Enterprise. Implacably, the guardian of the portal explains, “Your vessel, your beginning—all that you knew—is gone.” McCoy had somehow changed Earth’s history, with catastrophic results.
In desperation, Kirk and Spock go back in time to find McCoy, determine how he changed history, and stop him. Eventually Spock discovers that history pivots on the moment when McCoy saves a remarkable woman, Edith Keeler, from a fatal accident. Keeler went on to found a pacifist movement so powerful it delayed U.S. entry into World War II, allowing Nazi Germany time to develop the atomic bomb first. “With their A-bombs, and with their V-2 rockets to carry them,” Spock explains, “Germany captured the world.”
This imagined possibility provides one of the most compelling moments of the entire Star Trek series—and has provoked the imagination of many a history buff as well. But a determined spoilsport can poke a number of holes in it. To begin with, the Nazis never seriously pursued an atomic weapon. Even had they done so, limits on the production rate of fissionable material meant that at best, it would have required several weeks to manufacture a single atomic bomb. The massive rain of atomic bombs implicit in the Star Trek scenario was therefore out of the question. In any event, V-2 rockets could not have carried the immensely heavy early atomic bombs. The Nazis did not have a bomber with sufficient lift to carry them, either.
Moreover, if the Nazis had somehow reached cities in England and Russia, that would not necessarily have compelled these adversaries to surrender. Two atomic bombs barely sufficed to defeat Japan, and then only after the Japanese had suffered irreversible battlefield defeats and the fire-bombing of most of their cities. In telling contrast, historically the Red Army—although buffeted by disaster upon disaster—eluded strategic defeat and eventually assumed the offensive. Underscoring Soviet resilience was the fact they suffered 20 million dead—the equivalent of 200 Hiroshimas—and still continued to fight.
Yet another questionable assumption is that a German bomb would have been equivalent to the Hiroshima bomb. It could easily have been much less. India’s first nuclear test in 1974, for example, yielded only four kilotons (versus the 20 kilotons of the Hiroshima bomb).
It is also a virtual certainty that the shock of a German bomb would have shaken the United States from its pacifist reverie and sparked the launch of the Manhattan Project. Shielded from Nazi attack by the Atlantic Ocean, America would have eventually developed a bomb of its own, and used it either to deter further Nazi gains or, from bases in Britain or the Soviet Union, rained destruction upon Germany.
Thus it is impossible, even in the Star Trek universe, to imagine a plausible scenario by which Nazi Germany would have “captured the world.”
The probability of German victory through use of atomic bombs diminishes still further when one considers events as they actually unfolded, with America’s entry into the war in December 1941. Even granting Nazi acquisition of the bomb in July 1943—two years before the United States achieved this feat—and arbitrarily giving the Germans a bomber with a range and payload comparable to Britain’s Lancaster heavy bomber, the Third Reich would have faced not a single adversary comparable to 1945 Japan, but rather three nations firmly on the offensive and demonstrably winning the war. In such circumstances, a handful of atomic bombs would scarcely have compelled the Grand Alliance to surrender. Given that reality, how could Germany have best wielded its newly acquired weapon?
The most obvious approach, the destruction of cities á la Hiroshima, was in fact problematic. An attack on American cities was out of the question. The phenomenal capacity of the Soviet Union to absorb destruction would argue against the efficacy of simply destroying Russian cities. (Historically, the Siege of Leningrad claimed eight times the number of civilians killed in Nagasaki.) In any event, not even a Lancaster-like bomber could have reached the Soviet industrial centers beyond the Ural Mountains. London and a few other British cities might have been leveled, but would this have caused the British government to make a separate peace? Even had this occurred, would the United States have withdrawn from Britain? Or would it have taken the course adopted historically by Germany when Italy surrendered in 1943: assume de facto control over its former ally and use it as a platform on which to continue the fight?
A better approach, considering the numerous reversals of Germany’s fortune on the battlefield, would have been the tactical use of the bomb against enemy armies. For ideological reasons, the Nazis would have been tempted to target Soviet forces: from the outset, the Nazis had regarded Bolshevism as a menace that must be totally eradicated. But the fact that the Soviets had continued fighting despite the destruction of entire armies ought to have suggested that even nuclear attacks would not have stopped the Red Army.
The Western Allies would have made better targets, since they could only get at Germany via amphibious landings. Of necessity, such landings had to be geographically concentrated, making them ideal targets. German’s mere possession of an atomic bomb would therefore have rendered D-Day and a second front out of the question. Faced with this reality, it is just possible that the Soviets might have negotiated a separate peace with Germany.
What becomes highly probable, then, is that a protracted stalemate would have settled over Europe, finally disrupted when the United States acquired the bomb in July 1945 and employed it against Germany. World War II, not a hypothetical World War III, would thus have become the first nuclear conflict.
History Tells Us Why Russia Fears a NATO Invasion (Even If It Sounds Crazy)
While the idea of NATO attacking Russia may seem farfetched to most Americans, the Russians have reason to fear an invasion from the west. Over the past several centuries Russia has been repeatedly invaded by such powers as Poland, Sweden, France and Germany.
Russian state media has reported that the guard tank army of Russia's Western Military District has been reinforced to protect the country's western strategic border. Last month, Minister of Defense Sergei Shoigu told Tass that the western strategic direction remains under the highest threat for Russia's military security, adding that, in accordance with the 2019-2025 plan of action, Russia will conduct a complex series of measures to neutralize the potential threats.
"The Separate Guards Motorized Rifle Sevastopol Red Banner Brigade named after the 60th anniversary of the USSR was included in the Guards Red Banner Tank Army of the Western Military District to perform tasks on ensuring the defense of the Russian Federation in the Western strategic direction," the district’s press service said. "It is armed with modern weapons and military and specialized vehicles, such as T-90A tanks, BTR-82A armored carriers, BMP-3 combat vehicles, and 9A34 Strela-10 and 2S6M Tunguska air defense systems."
In addition, the motorized brigade has been deployed in the Novomoskovsky Administrative District of Moscow.
Earlier this month, head of the Main Directorate of the Russian Armed Forces' General Staff Sergei Rudskoi declared that the Russian Ministry of Defense consistently registered high level of military activity of the U.S. and its NATO allies near Russian borders. He added that the alliance had ramped up its exercises that bear a "distinct anti-Russian character."
While the idea of NATO attacking Russia may seem farfetched to most Americans, the Russians have reason to fear an invasion from the west. Over the past several centuries Russia has been repeatedly invaded by such powers as Poland, Sweden, France and Germany.
The United States also took part in what could be seen as an "invasion" of sorts when troops were sent to Russia during the nation's Civil War in 1918. The American military intervention at Archangel, Russia earning the nickname "Polar Bear Expedition" and it was actually to prevent the German advance and to help reopen the Eastern Front following Communist Russia's acceptance of the Treaty of Brest-Litovsk. Instead of fighting the Germans however, the American soldiers found themselves fighting Bolshevik forces.
Just two decades later Nazi Germany invaded the Soviet Union and drove deep into "Mother Russia," besieging Leningrad and reaching the gates of Moscow before winter set in and stopped the advance. Other Russian cities were occupied and by war's end many had been leveled – including Stalingrad, which had been the site of the mother-of-all battles and the turning point for the Germans.
Following the end of the Cold War and the dissolution of the Soviet Union, Russia is arguably more vulnerable while many of its former communist-era satellite states – including Poland, Hungary and Romania, along with the Czech and Slovak Republics – now being members of NATO.
Thus, it is not surprising that the Russian bear would be sharpening its claws – by upgrading its naval fleets and conducting regular military drills and exercises, while also developing new hardware such as with its T-14 Armata tank and its hypersonic undersea missiles.
Such military hardware could be seen not for their offensive capabilities, but rather as deterrents to ensure that Russia not face yet another invasion from the west.
Father of All Bombs
Aviation Thermobaric Bomb of Increased Power (ATBIP Russian: Авиационная вакуумная бомба повышенной мощности , АВБПМ),  nicknamed "Father of All Bombs" (FOAB Russian: "Папа всех бомб", Пвб ),  is a Russian-designed, bomber-delivered thermobaric weapon.
The bomb is reportedly similar to the US military's GBU-43/B Massive Ordnance Air Blast which is often unofficially called "Mother of All Bombs" derived from its official military acronym "MOAB". This weapon would therefore be the most powerful conventional (non-nuclear) weapon in the world.  However, the veracity of Russia's claims concerning the weapon's size and power have been questioned by US defense analysts. 
"FOAB" was successfully field-tested in the late evening of 11 September 2007.  The new weapon is to replace several smaller types of nuclear bombs in the Russian arsenal. 
Nuclear weapons have been used twice in war, both times by the United States against Japan near the end of World War II. On August 6, 1945, the U.S. Army Air Forces detonated a uranium gun-type fission bomb nicknamed "Little Boy" over the Japanese city of Hiroshima three days later, on August 9, the U.S. Army Air Forces detonated a plutonium implosion-type fission bomb nicknamed "Fat Man" over the Japanese city of Nagasaki. These bombings caused injuries that resulted in the deaths of approximately 200,000 civilians and military personnel.  The ethics of these bombings and their role in Japan's surrender are subjects of debate.
Since the atomic bombings of Hiroshima and Nagasaki, nuclear weapons have been detonated over 2,000 times for testing and demonstration. Only a few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and acknowledge possessing them—are (chronologically by date of first test) the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, China, India, Pakistan, and North Korea. Israel is believed to possess nuclear weapons, though, in a policy of deliberate ambiguity, it does not acknowledge having them. Germany, Italy, Turkey, Belgium and the Netherlands are nuclear weapons sharing states.    South Africa is the only country to have independently developed and then renounced and dismantled its nuclear weapons. 
The Treaty on the Non-Proliferation of Nuclear Weapons aims to reduce the spread of nuclear weapons, but its effectiveness has been questioned. Modernisation of weapons continues to this day. 
There are two basic types of nuclear weapons: those that derive the majority of their energy from nuclear fission reactions alone, and those that use fission reactions to begin nuclear fusion reactions that produce a large amount of the total energy output. 
All existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as atomic bombs or atom bombs (abbreviated as A-bombs). This has long been noted as something of a misnomer, as their energy comes from the nucleus of the atom, just as it does with fusion weapons.
In fission weapons, a mass of fissile material (enriched uranium or plutonium) is forced into supercriticality—allowing an exponential growth of nuclear chain reactions—either by shooting one piece of sub-critical material into another (the "gun" method) or by compression of a sub-critical sphere or cylinder of fissile material using chemically-fueled explosive lenses. The latter approach, the "implosion" method, is more sophisticated than the former.
A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of just under a ton to upwards of 500,000 tons (500 kilotons) of TNT (4.2 to 2.1 × 10 6 GJ). 
All fission reactions generate fission products, the remains of the split atomic nuclei. Many fission products are either highly radioactive (but short-lived) or moderately radioactive (but long-lived), and as such, they are a serious form of radioactive contamination. Fission products are the principal radioactive component of nuclear fallout. Another source of radioactivity is the burst of free neutrons produced by the weapon. When they collide with other nuclei in the surrounding material, the neutrons transmute those nuclei into other isotopes, altering their stability and making them radioactive.
The most commonly used fissile materials for nuclear weapons applications have been uranium-235 and plutonium-239. Less commonly used has been uranium-233. Neptunium-237 and some isotopes of americium may be usable for nuclear explosives as well, but it is not clear that this has ever been implemented, and their plausible use in nuclear weapons is a matter of dispute. 
The other basic type of nuclear weapon produces a large proportion of its energy in nuclear fusion reactions. Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs), as they rely on fusion reactions between isotopes of hydrogen (deuterium and tritium). All such weapons derive a significant portion of their energy from fission reactions used to "trigger" fusion reactions, and fusion reactions can themselves trigger additional fission reactions. 
Only six countries—United States, Russia, United Kingdom, China, France, and India—have conducted thermonuclear weapon tests. Whether India has detonated a "true" multi-staged thermonuclear weapon is controversial.  North Korea claims to have tested a fusion weapon as of January 2016 [update] , though this claim is disputed.  Thermonuclear weapons are considered much more difficult to successfully design and execute than primitive fission weapons. Almost all of the nuclear weapons deployed today use the thermonuclear design because it is more efficient. 
Thermonuclear bombs work by using the energy of a fission bomb to compress and heat fusion fuel. In the Teller-Ulam design, which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel (tritium, deuterium, or lithium deuteride) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma rays and X-rays emitted first compress the fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutrons, which can then induce fission in materials not normally prone to it, such as depleted uranium. Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary". In large, megaton-range hydrogen bombs, about half of the yield comes from the final fissioning of depleted uranium. 
Virtually all thermonuclear weapons deployed today use the "two-stage" design described above, but it is possible to add additional fusion stages—each stage igniting a larger amount of fusion fuel in the next stage. This technique can be used to construct thermonuclear weapons of arbitrarily large yield, in contrast to fission bombs, which are limited in their explosive force. The largest nuclear weapon ever detonated, the Tsar Bomba of the USSR, which released an energy equivalent of over 50 megatons of TNT (210 PJ), was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements. 
Fusion reactions do not create fission products, and thus contribute far less to the creation of nuclear fallout than fission reactions, but because all thermonuclear weapons contain at least one fission stage, and many high-yield thermonuclear devices have a final fission stage, thermonuclear weapons can generate at least as much nuclear fallout as fission-only weapons.
There are other types of nuclear weapons as well. For example, a boosted fission weapon is a fission bomb that increases its explosive yield through a small number of fusion reactions, but it is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb. There are two types of boosted fission bomb: internally boosted, in which a deuterium-tritium mixture is injected into the bomb core, and externally boosted, in which concentric shells of lithium-deuteride and depleted uranium are layered on the outside of the fission bomb core.
Some nuclear weapons are designed for special purposes a neutron bomb is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation such a device could theoretically be used to cause massive casualties while leaving infrastructure mostly intact and creating a minimal amount of fallout. The detonation of any nuclear weapon is accompanied by a blast of neutron radiation. Surrounding a nuclear weapon with suitable materials (such as cobalt or gold) creates a weapon known as a salted bomb. This device can produce exceptionally large quantities of long-lived radioactive contamination. It has been conjectured that such a device could serve as a "doomsday weapon" because such a large quantity of radioactivities with half-lives of decades, lifted into the stratosphere where winds would distribute it around the globe, would make all life on the planet extinct.
In connection with the Strategic Defense Initiative, research into the nuclear pumped laser was conducted under the DOD program Project Excalibur but this did not result in a working weapon. The concept involves the tapping of the energy of an exploding nuclear bomb to power a single-shot laser that is directed at a distant target.
During the Starfish Prime high-altitude nuclear test in 1962, an unexpected effect was produced which is called a nuclear electromagnetic pulse. This is an intense flash of electromagnetic energy produced by a rain of high-energy electrons which in turn are produced by a nuclear bomb's gamma rays. This flash of energy can permanently destroy or disrupt electronic equipment if insufficiently shielded. It has been proposed to use this effect to disable an enemy's military and civilian infrastructure as an adjunct to other nuclear or conventional military operations against that enemy. Because the effect is produced by high altitude nuclear detonations, it can produce damage to electronics over a wide, even continental, geographical area.
Research has been done into the possibility of pure fusion bombs: nuclear weapons that consist of fusion reactions without requiring a fission bomb to initiate them. Such a device might provide a simpler path to thermonuclear weapons than one that required the development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons because they would not disperse fission products. In 1998, the United States Department of Energy divulged that the United States had, ". made a substantial investment" in the past to develop pure fusion weapons, but that, "The U.S. does not have and is not developing a pure fusion weapon", and that, "No credible design for a pure fusion weapon resulted from the DOE investment". 
Antimatter, which consists of particles resembling ordinary matter particles in most of their properties but having opposite electric charge, has been considered as a trigger mechanism for nuclear weapons.    A major obstacle is the difficulty of producing antimatter in large enough quantities, and there is no evidence that it is feasible beyond the military domain.  However, the U.S. Air Force funded studies of the physics of antimatter in the Cold War, and began considering its possible use in weapons, not just as a trigger, but as the explosive itself.  A fourth generation nuclear weapon design  is related to, and relies upon, the same principle as antimatter-catalyzed nuclear pulse propulsion. 
Most variation in nuclear weapon design is for the purpose of achieving different yields for different situations, and in manipulating design elements to attempt to minimize weapon size. 
The system used to deliver a nuclear weapon to its target is an important factor affecting both nuclear weapon design and nuclear strategy. The design, development, and maintenance of delivery systems are among the most expensive parts of a nuclear weapons program they account, for example, for 57% of the financial resources spent by the United States on nuclear weapons projects since 1940. 
The simplest method for delivering a nuclear weapon is a gravity bomb dropped from aircraft this was the method used by the United States against Japan. This method places few restrictions on the size of the weapon. It does, however, limit attack range, response time to an impending attack, and the number of weapons that a country can field at the same time. With miniaturization, nuclear bombs can be delivered by both strategic bombers and tactical fighter-bombers. This method is the primary means of nuclear weapons delivery the majority of U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61.  [ needs update ]
Preferable from a strategic point of view is a nuclear weapon mounted on a missile, which can use a ballistic trajectory to deliver the warhead over the horizon. Although even short-range missiles allow for a faster and less vulnerable attack, the development of long-range intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) has given some nations the ability to plausibly deliver missiles anywhere on the globe with a high likelihood of success.
More advanced systems, such as multiple independently targetable reentry vehicles (MIRVs), can launch multiple warheads at different targets from one missile, reducing the chance of a successful missile defense. Today, missiles are most common among systems designed for delivery of nuclear weapons. Making a warhead small enough to fit onto a missile, though, can be difficult. 
Tactical weapons have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery shells, land mines, and nuclear depth charges and torpedoes for anti-submarine warfare. An atomic mortar has been tested by the United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as suitcase bombs), such as the Special Atomic Demolition Munition, have been developed, although the difficulty of combining sufficient yield with portability limits their military utility. 
Nuclear warfare strategy is a set of policies that deal with preventing or fighting a nuclear war. The policy of trying to prevent an attack by a nuclear weapon from another country by threatening nuclear retaliation is known as the strategy of nuclear deterrence. The goal in deterrence is to always maintain a second strike capability (the ability of a country to respond to a nuclear attack with one of its own) and potentially to strive for first strike status (the ability to destroy an enemy's nuclear forces before they could retaliate). During the Cold War, policy and military theorists considered the sorts of policies that might prevent a nuclear attack, and they developed game theory models that could lead to stable deterrence conditions. 
Different forms of nuclear weapons delivery (see above) allow for different types of nuclear strategies. The goals of any strategy are generally to make it difficult for an enemy to launch a pre-emptive strike against the weapon system and difficult to defend against the delivery of the weapon during a potential conflict. This can mean keeping weapon locations hidden, such as deploying them on submarines or land mobile transporter erector launchers whose locations are difficult to track, or it can mean protecting weapons by burying them in hardened missile silo bunkers. Other components of nuclear strategies included using missile defenses to destroy the missiles before they land, or implementing civil defense measures using early-warning systems to evacuate citizens to safe areas before an attack.
Weapons designed to threaten large populations or to deter attacks are known as strategic weapons. Nuclear weapons for use on a battlefield in military situations are called tactical weapons.
Critics of nuclear war strategy often suggest that a nuclear war between two nations would result in mutual annihilation. From this point of view, the significance of nuclear weapons is to deter war because any nuclear war would escalate out of mutual distrust and fear, resulting in mutually assured destruction. This threat of national, if not global, destruction has been a strong motivation for anti-nuclear weapons activism.
Critics from the peace movement and within the military establishment [ citation needed ] have questioned the usefulness of such weapons in the current military climate. According to an advisory opinion issued by the International Court of Justice in 1996, the use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, but the court did not reach an opinion as to whether or not the threat or use would be lawful in specific extreme circumstances such as if the survival of the state were at stake.
Another deterrence position is that nuclear proliferation can be desirable. In this case, it is argued that, unlike conventional weapons, nuclear weapons deter all-out war between states, and they succeeded in doing this during the Cold War between the U.S. and the Soviet Union.  In the late 1950s and early 1960s, Gen. Pierre Marie Gallois of France, an adviser to Charles de Gaulle, argued in books like The Balance of Terror: Strategy for the Nuclear Age (1961) that mere possession of a nuclear arsenal was enough to ensure deterrence, and thus concluded that the spread of nuclear weapons could increase international stability. Some prominent neo-realist scholars, such as Kenneth Waltz and John Mearsheimer, have argued, along the lines of Gallois, that some forms of nuclear proliferation would decrease the likelihood of total war, especially in troubled regions of the world where there exists a single nuclear-weapon state. Aside from the public opinion that opposes proliferation in any form, there are two schools of thought on the matter: those, like Mearsheimer, who favored selective proliferation,  and Waltz, who was somewhat more non-interventionist.   Interest in proliferation and the stability-instability paradox that it generates continues to this day, with ongoing debate about indigenous Japanese and South Korean nuclear deterrent against North Korea. 
The threat of potentially suicidal terrorists possessing nuclear weapons (a form of nuclear terrorism) complicates the decision process. The prospect of mutually assured destruction might not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a stateless terrorist instead of a sovereign nation, there might not be a nation or specific target to retaliate against. It has been argued, especially after the September 11, 2001, attacks, that this complication calls for a new nuclear strategy, one that is distinct from that which gave relative stability during the Cold War.  Since 1996, the United States has had a policy of allowing the targeting of its nuclear weapons at terrorists armed with weapons of mass destruction. 
Robert Gallucci argues that although traditional deterrence is not an effective approach toward terrorist groups bent on causing a nuclear catastrophe, Gallucci believes that "the United States should instead consider a policy of expanded deterrence, which focuses not solely on the would-be nuclear terrorists but on those states that may deliberately transfer or inadvertently leak nuclear weapons and materials to them. By threatening retaliation against those states, the United States may be able to deter that which it cannot physically prevent.". 
Graham Allison makes a similar case, arguing that the key to expanded deterrence is coming up with ways of tracing nuclear material to the country that forged the fissile material. "After a nuclear bomb detonates, nuclear forensics cops would collect debris samples and send them to a laboratory for radiological analysis. By identifying unique attributes of the fissile material, including its impurities and contaminants, one could trace the path back to its origin."  The process is analogous to identifying a criminal by fingerprints. "The goal would be twofold: first, to deter leaders of nuclear states from selling weapons to terrorists by holding them accountable for any use of their weapons second, to give leaders every incentive to tightly secure their nuclear weapons and materials." 
According to the Pentagon's June 2019 "Doctrine for Joint Nuclear Operations" of the Joint Chiefs of Staffs website Publication, "Integration of nuclear weapons employment with conventional and special operations forces is essential to the success of any mission or operation."  
German Social Democrat Karl Kautsky traces the origins of terrorism, including the terrorism seen in the Russian Empire, to the "Reign of Terror" of the French Revolution.   Others emphasize the role of Russian revolutionary movements during the 19th century, especially Narodnaya Volya ("People's Will") and the Nihilist movement, which included several thousand followers. "People's Will" organized one of the first political terrorism campaigns in history. In March 1881, it assassinated the Emperor of Russia Alexander II, who twenty years earlier had emancipated the Russian serfs. 
Important ideologists of these groups were Mikhail Bakunin and Sergey Nechayev, who was described in Fyodor Dostoevsky's novel The Possessed.  Nechayev argued that the purpose of revolutionary terror is not to gain the support of the masses, but on the contrary, to inflict misery and fear on the common population. According to Nechayev, a revolutionary must terrorize civilians in order to incite rebellions. He wrote: 
"A revolutionary must infiltrate all social formations including the police. He must exploit rich and influential people, subordinating them to himself. He must aggravate the miseries of the common people, so as to exhaust their patience and incite them to rebel. And, finally, he must ally himself with the savage word of the violent criminal, the only true revolutionary in Russia". "The Revolutionist is a doomed man. He has no private interests, no affairs, sentiments, ties, property nor even a name of his own. His entire being is devoured by one purpose, one thought, one passion - the revolution. Heart and soul, not merely by word but by deed, he has severed every link with the social order and with the entire civilized world with the laws, good manners, conventions, and morality of that world. He is its merciless enemy and continues to inhabit it with only one purpose - to destroy it."
According to historian and writer Edvard Radzinsky, Nechayev's ideas and tactics were widely used by Joseph Stalin and other Russian revolutionaries. 
The SR Combat Organization was founded in 1902 and operated as an autonomous branch of the Socialist Revolutionary Party responsible for assassinating government officials, was led by Grigory Gershuni and operated separately from the party so as not to jeopardize its political actions. SRCO agents assassinated two Ministers of the Interior, Dmitry Sipyagin and V. K. von Plehve, Grand Duke Sergei Aleksandrovich, the Governor of Ufa N. M. Bogdanovich, and many other high-ranking officials.  It has been estimated that all together in the last twenty years of the Tsarist regime (1897-1917) more than 17,000 people were killed or wounded in terror attacks. 
Red terror Edit
The policy of Red terror in Soviet Russia served to frighten the civilian population and exterminate certain social groups considered as "ruling classes" or enemies of the people. Karl Kautsky said about Red Terror: "Among the phenomena for which Bolshevism has been responsible, Terrorism, which begins with the abolition of every form of freedom of the Press, and ends in a system of wholesale execution, is certainly the most striking and the most repellent of all.. Kautsky recognized that Red Terror represented a variety of terrorism because it was indiscriminate, intended to frighten the civilian population, and included taking and executing hostages ". Martin Latsis, chief of the Ukrainian Cheka, emphasized that Red terror was an extrajudicial punishment not for specific acts, but membership in condemned social classes:
"Do not look in the file of incriminating evidence to see whether or not the accused rose up against the Soviets with arms or words. Ask him instead to which class he belongs, what is his background, his education, his profession. These are the questions that will determine the fate of the accused. That is the meaning and essence of the Red Terror." 
One of the most common terrorist practices was hostage-taking. A typical report from a Cheka department stated: "Yaroslavl Province, 23 June 1919. The uprising of deserters in the Petropavlovskaya volost has been put down. The families of the deserters have been taken as hostages. When we started to shoot one person from each family, the Greens began to come out of the woods and surrender. Thirty-four deserters were shot as an example". 
1977 Moscow bombings Edit
The 1977 Moscow bombings were allegedly organized by the Soviet KGB in Moscow to frame-up Armenian nationalists who were executed despite having an alibi.    
Accusations of terrorism Edit
Contemporary Russian government has been frequently accused of sponsoring or inspiring terrorist activities inside the country and in other countries in order to achieve its political goals.
Former FSB officer Alexander Litvinenko, Johns Hopkins University and Hoover Institute scholar David Satter,  Russian lawmaker Sergei Yushenkov, historian Yuri Felshtinsky, politologist Vladimir Pribylovsky and former KGB general Oleg Kalugin asserted that Russian apartment bombings were in fact a "false flag" attack perpetrated by the FSB (successor to the KGB) in order to legitimize the resumption of military activities in Chechnya and bring Vladimir Putin and the FSB to power. FSB operatives were actually briefly arrested in the case, but their presence at the crime scene was explained as "training".   This view was disputed by philosopher Robert Bruce Ware and Richard Sakwa,   [ dead link ]    but supported by historians Amy Knight   and Karen Dawisha 
Former FSB officer Aleksander Litvinenko and investigator Mikhail Trepashkin alleged that a Chechen FSB agent directed the Moscow theater hostage crisis in 2002.  
Yulia Latynina has accused the Russian security services of staging fake terrorist attacks (with minimal casualties) to report false successes in solving those cases, instead of investigating the actual terrorist attacks. 
Vyacheslav Izmailov from Novaya Gazeta has accused the Russian authorities of extorting confessions from suspect terrorists with torture, instead of engaging in genuine investigative efforts.  According to him, the kidnappings of journalists and members of international NGOs in 2005 in Chechnya, along with Andrei Babitsky from Radio Free Europe, Arjan Erkel and Kenneth Glack from Doctors Without Borders were organized by FSB agents. 
Alexander J. Motyl, professor of political science at Rutgers University argues that Russia's direct and indirect involvement in the violence in eastern Ukraine qualifies as a state-sponsored terrorism, and that those involved qualify as "terrorist groups." 
In May 2016, Reuters published a Special Report titled "How Russia allowed homegrown radicals to go and fight in Syria" that, based on first-hand evidence, said that at least in the period between 2012 and 2014 the Russian government agencies ran a programme to facilitate and encourage Russian radicals and militants to leave Russia and go to Turkey and then on to Syria the persons in question had joined jihadist groups, some fighting with the ISIL. According to the report, the goal has been to eradicate the risk of Islamic terrorism at home however Russian security officials deny that terrorists were encouraged to leave Russia. 
In 2018, after the poisoning of Skripals, the State Department was reportedly prepared to officially designate Russia as "state sponsor of terrorism" by US law based on the cases described above, but the work has been stopped as it was decided that it would interefere with US options in areas where it has to cooperate with Russia. 
In April 2019 Security Service of Ukraine arrested 7 Russians traveling on counterfeit passports accused of preparing a car bombing against a Ukrainian military intelligence officer. One of them, traveling with fake Kyrgyzstan passport, was identified as Timur Dzortov, previously deputy chief of staff to the leader Ingushetia. Another man, responsible for actually planting the bomb in the car, accidentally triggered it and was wounded by the blast. SBU accused officer Dmitry Minayev from Russian Federal Security Service (FSB) of coordinating the group. 
1999 Russian apartment bombings Edit
The Russian apartment bombings were a series of bombings in Russia that killed nearly 300 people and, together with the Dagestan War, led the country into the Second Chechen War. The four bombings took place in the Russian cities of Buinaksk, Moscow and Volgodonsk during early days of September 1999. 
The bombings were followed by a controversial episode when a suspected bomb was found and defused in an apartment block in the Russian city of Ryazan on 22 September, which was then explained to be an exercise by the Russian security services, the FSB. 
An official investigation of the bombings was completed only three years later, in 2002. Seven suspects were killed, six have been convicted on terrorism-related charges, and one remains a fugitive. According to the investigation, the Moscow and Volgodonsk bombings were organized and led by Achemez Gochiyaev, who headed a group of Karachai Wahhabis, while the Buinaksk bombing was organized and perpetrated by a different group of Dagestani Wahhabis. 
The Russian Duma rejected two motions for parliamentary investigation of the Ryazan incident. An independent public commission to investigate the bombings chaired by Duma deputy Sergei Kovalev was rendered ineffective because of government refusal to respond to its inquiries. Two key members of the Kovalev Commission, Sergei Yushenkov and Yuri Shchekochikhin, both Duma members, have since died in assassinations in April 2003 and July 2003 respectively. The Commission's lawyer Mikhail Trepashkin was arrested in October 2003 to become one of the better-known political prisoners in Russia.   
More recent attacks Edit
The Moscow theater hostage crisis (also known as the 2002 Nord-Ost siege) was the seizure of a crowded Dubrovka Theater by 40 to 50 armed Chechens on 23 October 2002 that involved 850 hostages and ended with the deaths of at least 170 people.
In September 2004, following bombing attacks on two aircraft and the downtown Moscow Metro, Chechen terrorists seized over 1,000 hostages at a school in Beslan, North Ossetia.
The 2006 Moscow market bombing occurred on August 21, 2006, when a self-made bomb of the power of more than 1 kg of TNT exploded at Moscow's Cherkizovsky Market frequented by foreign merchants.  The bombing killed 13 people and injured 47. In 2008, eight members of the neo-Nazi organization The Saviour were sentenced for their roles in the attack. 
In March 2010 suicide bombings were carried out by two women who were aligned with Caucasus Emirate and Al-Qaeda. The terrorist attack happened during the morning rush hour of March 29, 2010, at two stations of the Moscow Metro (Lubyanka and Park Kultury), with roughly 40 minutes interval between. At least 38 people were killed, and over 60 injured.  
The Domodedovo International Airport bombing was a suicide bombing in the international arrival hall of Moscow's Domodedovo International, in Domodedovsky District, Moscow Oblast, on 24 January 2011.
The bombing killed 37 people  and injured 173 others, including 86 who had to be hospitalised.  Of the casualties, 31 died at the scene, three later in hospitals, one en route to a hospital,  one on 2 February after having been put in a coma, and another on 24 February after being hospitalised in grave condition. 
Russia's Federal Investigative Committee later identified the suicide bomber as a 20-year-old from the North Caucasus, and said that the attack was aimed "first and foremost" at foreign citizens. 
In December 2013, two separate suicide bombings a day apart targeted mass transportation in the city of Volgograd, in the Volgograd Oblast of Southern Russia, killing 34 people overall, including both perpetrators who were aligned to Caucasus Emirate and Vilayat Dagestan. The attacks followed a bus bombing carried out in the same city two months earlier. [ citation needed ]
On 21 October 2013, a suicide bombing took place on a bus in the city of Volgograd, in the Volgograd Oblast of Southern Russia. The attack was carried out by a female perpetrator named Naida Sirazhudinovna Asiyalova (Russian: Наида Сиражудиновна Асиялова) who was converted to Islam by her husband, she detonated an explosive belt containing 500–600 grams of TNT inside a bus carrying approximately 50 people, killing seven civilians and injuring at least 36 others. 
On October 5, 2014 a 19-year-old man named Opti Mudarov went to the town hall where an event was taking place to mark Grozny City Day celebrations in Grozny coinciding with the birthday of Chechen President Ramzan Kadyrov. Police officers noticed him acting strangely and stopped him. The officers began to search him and the bomb which Mudarov had been carrying exploded. Five officers, along with the suicide bomber, were killed, while 12 others were wounded. 
On 4 December 2014, a group of Islamist militants, in three vehicles, killed three traffic policemen, after the latter had attempted to stop them at a checkpoint in the outskirts of Grozny.  The militants then occupied a press building and an abandoned school, located in the center of the city. Launching a counter-terrorism operation, security forces, with the use of armored vehicles, attempted to storm the buildings and a firefight ensued. 
14 policemen, 11 militants and 1 civilian were killed. Additionally 36 policemen were wounded in the incident. The Press House was also burned and severely damaged in the incident.  
Metrojet Flight 9268 was an international chartered passenger flight operated by Russian airline Kogalymavia (branded as Metrojet). On 31 October 2015 at 06:13 local time EST (04:13 UTC), an Airbus A321-231 operating the flight disintegrated above the northern Sinai following its departure from Sharm El Sheikh International Airport, Egypt, in route to Pulkovo Airport, Saint Petersburg, Russia. All 217 passengers and seven crew members who were on board were killed.   
Shortly after the crash, the Islamic State of Iraq and the Levant (ISIL)'s Sinai Branch, previously known as Ansar Bait al-Maqdis, claimed responsibility for the incident, which occurred in the vicinity of the Sinai insurgency.   ISIL claimed responsibility on Twitter, on video, and in a statement by Abu Osama al-Masri, the leader of the group's Sinai branch.   ISIL posted pictures of what it said was the bomb in Dabiq, its online magazine.
By 4 November 2015, British and American authorities suspected that a bomb was responsible for the crash. On 8 November 2015, an anonymous member of the Egyptian investigation team said the investigators were "90 percent sure" that the jet was brought down by a bomb. Lead investigator Ayman al-Muqaddam said that other possible causes of the crash included a fuel explosion, metal fatigue, and lithium batteries overheating.  The Russian Federal Security Service announced on 17 November that they were sure that it was a terrorist attack, caused by an improvised bomb containing the equivalent of up to 1 kilogram (2.2 lb) of TNT that detonated during the flight. The Russians said they had found explosive residue as evidence. On 24 February 2016, Egyptian President Abdel Fattah el-Sisi acknowledged that terrorism caused the crash. 
On 3 April 2017, a terrorist attack using an explosive device took place on the Saint Petersburg Metro between Sennaya Ploshchad and Tekhnologichesky Institut stations.  Seven people (including the perpetrator) were initially reported to have died, and eight more died later from their injuries, bringing the total to 15.      At least 45 others were injured in the incident.   The explosive device was contained in a briefcase.  A second explosive device was found and defused at Ploshchad Vosstaniya metro station.  The suspected perpetrator was named as Akbarzhon Jalilov, a Russian citizen who was an ethnic Uzbek born in Kyrgyzstan.  Prior to the attack, Chechen separatists had been responsible for several terrorist attacks in Russia. In 2016, ISIS had plotted to target St. Petersburg due to Russia's military involvement in Syria, resulting in arrests.  No public transport system in Russia had been bombed since the 2010 Moscow Metro bombings.  ISIS propaganda was being circulated prior to this incident. It encouraged supporters to launch strikes on Moscow. ISIS propaganda showed bullet holes through Putin's head and a poster circulated before the attack of a falling Kremlin and included the message "We Will Burn Russia." 
In 22 April 2017, two people were shot and killed in an attack in a Federal Security Service office in the Russian city of Khabarovsk. The gunman was also killed. The Russian Federal Security Service said that the native 18-year-old perpetrator was a known member of a neo-nazi group. 
On 27 December 2017 a bomb exploded in a supermarket in St Petersburg, injuring thirteen people. Vladimir Putin described this as a terrorist attack. 
In December 2019 President of Russia Vladimir Putin thanked his American counterpart Donald Trump for a tip which allowed to prevent a terrorist attack in St. Petersburg.