The resolution of the Namibian problem has considerably lessened the level of tension in Southern Africa, but there are still many other areas of conflict which remain unresolved. The settlement in Namibia has shown that the problems of Southern Africa, which are in many respects interdependent, should be resolved step by step, or at least independently of the dismantling of the apartheid system. SWAPO detachments stationed in Angola crossed the frontier and provoked armed clashes with Namibia's security forces. In the summer of 1991, many unexpected changes occurred in Southern Africa, such as the changes in South African apartheid policy, the completion of troop withdrawal from Angola, the decolonization of Namibia, and the termination of South Africa's interference in the internal affairs of neighboring countries. One important factor was the general change in international relations. Another factor was the constant support of the international community to end colonialism and racism, especially in Namibia and South Africa.