The Soviet Union, although it did not take direct military action, provided intelligence and equipment support for Vietnam. A large airlift was established by the Soviet Union to move Vietnamese troops from Cambodia to Northern Vietnam. Moscow also provided a total of 400 tanks and armored personnel carriers (APCs), 500 mortar artillery and air defense artillery, 50 BM-21 rocket launchers, 400 portable surface-to-air missiles, 800 anti-tank missiles and 20 jet fighters. About 5,000 to 8,000 Soviet military advisers were present in Vietnam in 1979 to train Vietnamese soldiers.