The Sandinista insurgency in Nicaragua, which led to the demise of the Somoza dictatorship in 1979, was openly supported by Cuba. However, it was on the African continent where Cuba was most active, supporting a total of 17 liberation movements or leftist governments, in countries including Angola, Equatorial Guinea, Ethiopia, Guinea-Bissau, and Mozambique. Cuba offered to send troops to Vietnam, but the initiative was turned down by the Vietnamese. Cuba had some 39,000–40,000 military personnel abroad by the late 1970s, with the bulk of the forces in Sub-Saharan Africa but with some 1,365 stationed among Algeria, Iraq, Libya, and South Yemen. Its Angolan involvement was particularly intense and noteworthy with heavy assistance given to the Marxist–Leninist MPLA in the Angolan Civil War. Cuban soldiers were instrumental in the defeat of South African and Zairian troops. Cuban soldiers also defeated the FNLA and UNITA armies and established MPLA control over most of Angola. Cuba's presence in Mozambique was more subdued, involving by the mid-1980s 700 Cuban military and 70 civilian personnel. In 1978, in Ethiopia, 16,000 Cuban combatants, along with the Soviet-supported Ethiopian army, defeated an invasion force of Somalians. South African soldiers were again drawn into the Angolan Civil War in 1987–88, and several inconclusive battles were fought between Cuban and South African forces. Cuban-piloted MiG-23s performed airstrikes against South African forces in Namibia during the Battle of Cuito Cuanavale.