A thermonuclear weapon weighing little more than 2,400 pounds (1,100 kg) can produce an explosive force comparable to the detonation of more than 1.2 million tons of TNT. A nuclear device no larger than traditional bombs can devastate an entire city by blast, fire, and radiation. Nuclear weapons are considered weapons of mass destruction, and their use and control has been a major focus of international relations policy since their debut.
The Treaty on the Non-Proliferation of Nuclear Weapons, commonly
known as the Non-Proliferation Treaty or NPT, is an international treaty
whose objective is to prevent the spread of nuclear weapons and weapons
technology, to promote cooperation in the peaceful uses of nuclear
energy, and to further the goal of achieving nuclear disarmament and
general and complete disarmament.
Five states have signed up to NPT, the US, UK, Russia, France and
China. Between them they have declared 22,000 nuclear weapons in
stock. These five Nuclear Weapons States (NWS) have made undertakings
not to use their nuclear weapons against a non-NWS party except in
response to a nuclear attack. India, Pakistan and N.Korea have also
declared stocks of nuclear weapons. Israel is widely known to have
nuclear weapons but does not declare it.