Comprehensive Test Ban Treaty is an international agreement prohibiting all tests of nuclear weapons. The United Nations General Assembly approved the treaty in 1996, and more than 150 nations have signed it. To formally enter into force, the agreement must be ratified by 44 nations named in the treaty. All 44 countries have nuclear reactors (devices for producing nuclear energy). The group also includes all nations that either have, or are suspected of having, nuclear weapons. Among these countries are China, France, India, Israel, Pakistan, Russia, the United Kingdom, and the United States. Ratification seems unlikely because India and Pakistan have refused even to sign the treaty. However, all nations that have signed the pact are expected to abide by it even if it does not formally go into effect.