Negotiations to bring an end to the war started in 1968 and ended in 1973. The United States, the USSR, the North Vietnamese, and the Vietcong all signed an agreement that stated: the US must withdraw all troops from Vietnam, all POWs were to be released, all military activity in Cambodia and Laos were to end, and North and South Vietnam were to continue to be split along the 17th parallel. (dec 28, 1967