than 300 wounded. They remained in South Korea after the cease fire, returning to Thailand in 1955. Vietnam War (1955–1975) Due to its proximity to Thailand, Vietnam's conflicts were closely monitored by Bangkok. Thai involvement did not become official until the total involvement of the United States in support of South Vietnam in 1963. The Thai government then allowed the United States Air Force in Thailand to use its air and naval bases. At the height of the war, almost 50,000 American military personnel were stationed in Thailand, mainly airmen. In October 1967 a regiment-size Thai unit, the Queen's Cobras, were sent to Camp Bearcat at Bien Hoa, to fight alongside the Americans, Australians, New Zealanders and South Vietnamese. About 40,000 Thai military would serve in South Vietnam, with 351 killed in action and 1,358 wounded. Thai troops earned a reputation for bravery and would serve in Vietnam until 1971, when the men of the Royal Thai Army Expeditionary Division (Black Panthers) returned home. Thailand was also involved in the Laotian Civil War, supporting covert operations against the communist Pathet Lao and the North Vietnamese from 1964 to 1972. By 1975 relations between Bangkok and Washington had soured, and the government of Kukrit Pramoj requested the withdrawal of all US military personnel and the closure of all US bases. This was completed by March 1976. Communist insurgency (1976–1980s) The communist victory in Vietnam in 1975 emboldened the communist movement in Thailand, which had been in existence since the 1920s. After the Thammasat University massacre of leftist student demonstrators in 1976 and the repressive policies of right-wing Prime Minister Tanin Kraivixien, sympathies for the movement increased. By the late-1970s, it is estimated that the movement had as many as 12,000 armed insurgents, mostly based in the northeast along the Laotian border and receiving foreign support. By the 1980s, however, all insurgent activities had been defeated. In 1982 Prime Minister Prem Tinsulanonda issued a general amnesty for all former communist insurgents. Vietnamese border raids (1979–1988) With the Vietnamese invasion of Cambodia in 1978, communist Vietnam had a combined force of about 300,000 in Laos and Cambodia. This posed a massive potential threat to the Thais, as they could no longer rely on Cambodia to act as a buffer state. Small encounters occasionally took place when Vietnamese forces crossed into Thailand in pursuit of fleeing Khmer Rouge troops. However, a full and official