Cuban intervention in Angola the requested financial assistance (100,000US$) it received from Yugoslavia. Portugal's sudden retreat from Angola and Mozambique in 1975 ended a history of South African military and intelligence cooperation with Portugal against the Angolan and Namibian independence movements dating back to the 1960s, later formalized in a secret alliance codenamed Alcora Exercise. It also ended economic cooperation with regard to the Cunene hydro-project at the Angolan-Namibian border, which South Africa had financed. South African involvement in Angola, subsumed under what it called the South African Border War, started in 1966 when the conflict with the Namibian independence movement, South West Africa
Angola–Namibia relations the fighting in Namibia would eventually drive at least 43,000 Namibian refugees into exile in Angola, many of whom joined PLAN. Following Angolan independence in 1975, SWAPO established a formal alliance with Angola's new ruling party, the People's Movement for the Liberation of Angola (MPLA). After being expelled from Zambia between 1976 and 1979, PLAN was permitted by the MPLA to establish its regional headquarters inside Angola. Access to bases inside Angola provided PLAN with opportunities to train its forces in secure sanctuaries and infiltrate insurgents and supplies across Namibia's northern border. The MPLA government also permitted shipments of arms