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.
Treaty on the Prohibition of Nuclear Weapons
According to the International Campaign to Abolish Nuclear Weapons (ICAN), a coalition of non-governmental organizations, leading proponents of a nuclear-weapon-ban treaty include Ireland, Austria, Brazil, Indonesia, Mexico, Nigeria, South Africa and Thailand. All 54 nations of Africa (all but one of which have either signed or ratified the 1996 Treaty of Pelindaba establishing a nuclear-weapon-free-zone in the continent) and all 33 nations of Latin America and the Caribbean (already in a nuclear-weapon-free-zone under the 1967 Treaty of Tlatelolco) had subscribed to common regional positions supporting a ban treaty. The 10 nations of the Association of Southeast Asian Nations (ASEAN), which concluded the Southeast Asian Nuclear-Weapon-Free Zone Treaty, participated in the negotiations, but Singapore abstained from the vote. Many Pacific island nations are also supportive.