The mid-Pacific nation of Palau has ratified the Comprehensive Nuclear Test Ban Treaty, bringing to 139 the number of nations that have fully endorsed the pact, the Vienna-based organization that administers the accord said Tuesday. Palau's ratification is important because it hosts a monitoring station that will help create a global alarm system now being built to monitor compliance with the pact, the Comprehensive Nuclear-Test-Ban Treaty Organization said. However, the treaty - which bans all nuclear explosions - will not enter into force until it has been ratified by 44 states listed in an annex which participated in a 1996 disarmament conference and have nuclear power or research reactors. Only 34 of the 44 countries have both signed and ratified the pact, the organization said. They include Britain, France and Russia, all of which have nuclear weapons. The holdouts are China, Colombia, Egypt, India, Indonesia, Iran, Israel, Pakistan, North Korea and the United States.