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 and Ukraine
After the dissolution of the Soviet Union, Ukraine held about one third of the Soviet nuclear arsenal, the third largest in the world at the time, as well as significant means of its design and production. 130 UR-100N intercontinental ballistic missiles (ICBM) with six warheads each, 46 RT-23 Molodets ICBMs with ten warheads apiece, as well as 33 heavy bombers, totalling approximately 1,700 warheads remained on Ukrainian territory. Formally, these weapons were controlled by the Commonwealth of Independent States. In 1994 Ukraine agreed to destroy the weapons, and to join the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).