South African forces feared the threat of a "domino effect" in favour of communism, represented in southern Africa by Cuban forces in Angola, aiding Angolan Marxist-Leninist revolutionary groups against rivals supported by South African forces, and threatening Namibia. In 1988, South Africa signed the Tripartite Accord with Cuba and Angola, which led to the withdrawal of South African and Cuban troops from Angola and independence for Namibia. The pre-emptive elimination of nuclear weapons was expected to make a significant contribution toward regional stability and peace, and also to help restore South Africa's credibility in regional and international politics. F.W. de Klerk saw the presence of nuclear weapons in South Africa as a problem. De Klerk disclosed the information about his weapons to the United States in an effort to get the weapons removed.