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 artillery
Belgium, Canada, Germany, Greece, Italy, Netherlands, Turkey, and the United Kingdom provided artillery units trained in the correct handling and operation of nuclear weapons and in some cases specialist logistic and security units. Their allocated nuclear weapons were in the custody of US Army Artillery Groups (USAAG) with subordinate US Army Field Artillery Detachments (USAFAD) assigned to the national artillery units. The Groups were part of the 59th Ordnance Brigade.