Direct U.S. military involvement ended on 15 August 1973. The capture of Saigon by the North Vietnamese Army in April 1975 marked the end of the war, and North and South Vietnam were reunified the following year. The war exacted a huge human cost in terms of fatalities (see Vietnam War casualties).he People's Army of Vietnam, also known as the North Vietnamese Army (NVA), engaged in a more conventional war, at times committing large units to battle. As the war continued, the part of the Viet Cong in the fighting decreased as the role of the NVA grew.