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.
Military history of the Soviet Union
Most of the nuclear stockpile was inherited by Russia. Additional weapons were acquired by Ukraine, Belarus and Kazakhstan. Amid fears of nuclear proliferation, these were all certified as transferred to Russia by 1996. Uzbekistan is another former Soviet republic where nuclear weapons may once have been stationed, but they are now signers of the Nuclear non-proliferation treaty.