The MLPA, with the support of Cuban troops as well as backing by the Soviet Union and other communist parties, quickly gained control of Luanda and the government, and the UNITA, allied with the tribal National Liberation Front of Angola (FNLA) was restricted to the country's interior. The first UN peacekeeping mission to Angola, United Nations Angola Verification Mission I (UNAVEM I) oversaw the agreed upon Cuban withdrawal in 1988. That same year, the South African troops supporting UNITA were withdrawn and by 1990 the belligerents, joined by eighteen other African nations agreed to a ceasefire.