President Vladimir Putin says Russia has struck a deal with neighbouring Belarus to station tactical nuclear weapons on its territory.
He said on Saturday that the agreement will not violate nonproliferation agreements.
The following are details of Russia’s nuclear arsenal, how big it is and who commands it.
Russia, which inherited the Soviet Union’s nuclear weapons, has the world’s biggest stockpile of nuclear warheads.
Putin controls about 5,977 such warheads as of 2022, compared with 5,428 controlled by United States President Joe Biden, according to the Federation of American Scientists.
An estimated 1,500 of those warheads are retired (but probably still intact), 2,889 are in reserve and 1,588 are deployed strategic warheads.
The Bulletin of the Atomic Scientists said 812 are deployed on land-based ballistic missiles, 576 on submarine-launched ballistic missiles and about 200 at heavy bomber bases.
The US has 1,644 deployed strategic nuclear warheads.
China has a total of 350 warheads, France 290 and the United Kingdom 225, according to the Federation of American Scientists.
Such numbers mean that both Moscow and Washington could destroy the world many times over.
During the Cold War, the Soviet Union’s arsenal reached a peak of about 40,000 nuclear warheads while the US peak was about 30,000 warheads.
The key, though, is how to deliver the weapon – the missiles, submarines and bombers that carry the warheads.
Russia appears to have about 400 nuclear-armed intercontinental ballistic missiles, which the Bulletin of the Atomic Scientists estimated can carry up to 1,185 warheads.
Russia operates 10 nuclear-armed nuclear submarines, which could carry a maximum of 800 warheads. It has 60 to 70 nuclear bombers.
The US said in its 2022 Nuclear Posture Review that Russia and China were expanding and modernising their nuclear forces and Washington would pursue an approach based on arms control to head off costly arms races.
Putin said he had information that the US was developing new types of nuclear weapons.
Since the Soviet Union collapsed in 1991, only a few countries have tested nuclear weapons, according to the Arms Control Association: the US last in 1992, China and France last in 1996, India and Pakistan in 1998, and North Korea last in 2017.
The Soviet Union last tested in 1990.
Who may give Russian launch orders?
The Russian president is the ultimate decision-maker when it comes to using Russian nuclear weapons, both strategic and nonstrategic, according to Russia’s nuclear doctrine.
The so-called nuclear briefcase, or “Cheget” (named after Mount Cheget in the Caucasus Mountains), is with the president at all times.
The Russian defence minister, currently Sergey Shoigu, and the chief of the general staff, now Valery Gerasimov, are also thought to have such briefcases.
Essentially, the briefcase is a communication tool that links the president with his top military brass and thence to rocket forces via the highly secret “Kazbek” electronic command-and-control network. Kazbek supports another system known as “Kavkaz”.
Footage shown by Russia’s Zvezda television channel in 2019 showed what it said was one of the briefcases with an array of buttons.
In a section called “command”, there are two buttons: a white “launch” button and a red “cancel” button. The briefcase is activated by a special flashcard, according to Zvezda.
If Russia thought it faced a strategic nuclear attack, the president, via the briefcases, would send a direct launch order to general staff command and reserve command units, which hold the nuclear codes.
Such orders cascade swiftly down different communications systems to strategic rocket force units, which then would fire at the targets.
If a nuclear attack were confirmed, Putin could activate the so-called “Dead Hand”, or “Perimetr” system of last resort. Essentially computers would decide doomsday. A control rocket would order nuclear strikes from across Russia’s vast armoury.