HONG KONG, MAY 16 -- China admitted today that it sent 320,000 combat troops to Vietnam to fight against U.S. forces and their South Vietnamese allies. In a report monitored in Hong Kong, the semi-official China News Service said China sent the soldiers to Vietnam during the 1960s and spent over $20 billion to support Hanoi's regular North Vietnamese Army and Viet Cong guerrilla units. The disclosure was made a month after military officials in the Soviet Union admitted that a contingent of Soviet advisers in Vietnam took part in combat against U.S. forces and helped shoot down American planes. Moscow had previously denied its troops played a combat role in the war. The agency report cited "The History of the People's Republic of China," published by the official State Archives Publishing House, as saying more than 4,000 Chinese soldiers were killed during the war. Fighting finally ended when victorious North Vietnamese tanks battered their way into the grounds of Doc Lap Palace in Saigon on April 30, 1975. During the war, U.S. intelligence reports said U.S. combat units had found soldiers dressed in Chinese combat gear and wearing Chinese insignia, but Beijing at the time repeatedly denied U.S. allegations that its soldiers were operating in Vietnam. During the 10 years of direct U.S. involvement, American troop levels reached over 500,000. Estimates of North Vietnamese Army units varied, but Hanoi maintained throughout the war that its soldiers went only as volunteers to help the southern Viet Cong guerrilla movement.