Determined to overwhelm UNITA, government forces launched the largest offensive yet seen in the conflict: Operation Second Congress. Devised by Soviet and Cuban military advisors, the offensive called for simultaneous attacks on Cazombo and Mavinga. South Africa, realizing the threat, launched several operations to support UNITA. The outcome of the fighting was mixed for both sides. Despite Cazombo being retaken by government forces, Mavinga successfully held out. Intent on a rematch, planning for the next offensive began. Likewise, operations to disrupt another offensive also began. Sources used:

• Adrien Fontanellaz's, Tom Cooper's, and José Augusto Matos' "War of Intervention in Angola: Volume 4 - Angolan and Cuban Air Forces, 1985-1987"
• John Turner's "Continent Ablaze: The Insurgency Wars in Africa 1960 to the Present"
• Edward George's "The Cuban Intervention in Angola 1965-1991 From Che Guevara to Cuito Cuanavale"
• Stephen Weigert's "Angola: A Modern Military History, 1961-2002"