Weapon of mass destruction
The only country to have used a nuclear weapon in war is the United States, which dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki during World War II. There are eight countries that have declared they possess nuclear weapons and are known to have tested a nuclear weapon, only five of which are members of the NPT. The eight are China, France, India, North Korea, Pakistan, Russia, the United Kingdom, and the United States.
Nuclear weapons convention
Each year since 1996, the UN General Assembly has passed a resolution calling on all countries immediately to fulfill their disarmament obligation, as articulated by the International Court of Justice, "by commencing multilateral negotiations leading to an early conclusion of a nuclear weapons convention." In 2007, 127 countries voted in favour of the resolution, including four countries with nuclear weapons: China, India, Pakistan and North Korea.