In August 1975, the MPLA requested direct assistance from the Soviet Union in the form of ground troops. The Soviets declined, offering to send advisers but no troops; however, Cuba was more forthcoming and in late September dispatched nearly five hundred combat personnel to Angola, along with sophisticated weaponry and supplies. By independence, there were over a thousand Cuban soldiers in the country. They were kept supplied by a massive airbridge carried out with Soviet aircraft. The persistent buildup of Cuban and Soviet military aid allowed the MPLA to drive its opponents from Luanda and blunt an abortive intervention by Zairean and South African troops, which had deployed in a belated attempt to assist the FNLA and UNITA. The FNLA was largely annihilated, although UNITA managed to withdraw its civil officials and militia from Luanda and seek sanctuary in the southern provinces. From there, Savimbi continued to mount a determined insurgent campaign against the MPLA.