<P> During the war, the South Vietnamese President Ngo Dinh Diem began a program to settle ethnic Vietnamese Kinh on Montagnard lands in the Central Highlands region . This provoked a backlash from the Montagnards . The Cambodians under both the pro-China King Sihanouk and the pro-American Lon Nol supported their fellow co-ethnic Khmer Krom in south Vietnam, following an anti-ethnic Vietnamese policy . </P> <P> A large number of war crimes took place during the Vietnam War . War crimes were committed by both sides during the conflict and included rape, massacres of civilians, bombings of civilian targets, terrorism, the widespread use of torture and the murder of prisoners of war . Additional common crimes included theft, arson, and the destruction of property not warranted by military necessity . </P> <P> In 1968, the Vietnam War Crimes Working Group (VWCWG) was established by the Pentagon task force set up in the wake of the My Lai Massacre, to attempt to ascertain the veracity of emerging claims of war crimes by U.S. armed forces in Vietnam, during the Vietnam War period . </P> <P> Sworn statements by witnesses and status reports for top military officers indicated that 320 incidents had factual basis . The substantiated cases included 7 massacres between 1967 and 1971 in which at least 137 civilians were killed; seventy eight further attacks targeting non-combatants resulting in at least 57 deaths, 56 wounded and 15 sexually assaulted; one hundred and forty - one cases of US soldiers torturing civilian detainees or prisoners of war with fists, sticks, bats, water or electric shock . Journalism in the ensuing years has documented large numbers of overlooked war crimes involving every army division that was active in Vietnam . </P>

When did we go to war with vietnam