The Carnegie Endowment for International Peace, a nonprofit organization in Washington, D.C., offers the full text of the Nuclear Non-Proliferation Treaty, which was entered into force on March 5, 1970. Signers of this treaty have agreed to give up their nuclear weapons. In 1995 the signers agreed upon an indefinite extension of the treaty. The five declared nuclear weapons states are the United States, Great Britain, China, France, and Russia.