Escalation of the conflict
As a result of the South African Operation Askari in December 1983, which targeted PLAN bases inside Angola, the USSR not only increased its aid to Angola but also took over the tactical and strategic leadership of FAPLA deploying advisors right down to the battalion level and begun planning a large-scale offensive against the UNITA-stronghold in southeastern Angola.
Soviet command did not include the Cuban forces in Angola. Cuba's strategic opinions differed considerably from those of the Soviets and Angolans and Cuba strongly advised against an offensive in the southeast because it would create the opportunity for a significant South African invasion, which is what transpired.A FAPLA-offensive in 1984 had already brought dismal results. Under Soviet leadership the FAPLA launched two more offensives in 1985 and 1986. The Cubans deny involvement in the 1985 operation but supported the offensive in 1986 despite of many reservations, not providing ground forces but technical and air support. Apart from taking Cazombo in 1985, coming close to Mavinga and bringing UNITA close to defeat, both offensives ended up in a complete failure and became a major embarrassment for the Soviets. Unlike the Cubans with ten years of experience in the African theatre, the Soviet leadership was inexperienced and relations between the two became strained. In addition, in March 1985 Mikhail Gorbachev had become the new General Secretary with whom Castro had considerable disagreements. In both FAPLA-offensives South Africa, still controlling the lower reaches of southwestern Angola, intervened as soon as UNITA came into distress. In September 1985, the South African Air Force prevented the fall of Mavinga and the FAPLA-offensive ended at the Lomba River.
After this debacle in 1985, the Soviets sent more equipment and advisors to Angola and immediately went about to prepare another FAPLA-offensive in the following year. In the meantime UNITA received its first military aid from the US, which included surface-to-airStinger missiles and BGM-71 TOW anti-tank-missiles. The US sent supplies to UNITA and SADF through the reactivated KaminaAirbase in Zaire. The offensive starting in May 1986 already got off to a poor start and again with the help of the SADF UNITA managed to stop the advance by late August.