The Treaty on the Prohibition of Nuclear Weapons in Latin America was signed on February 14, 1967 by 21 countries of Latin America. The Treaty on the Prohibition of Nuclear Weapons in Latin America was signed on February 14, 1967 by 14 countries of Latin America, including Mexico, Chile and others. The Treaty came into force on September 20, 1967 for the first time for Mexico. By 1995, 33 countries of Latin America had all signed it, 28 of them ratified it and entered into force.