Viet Cong (vēĕt´ kông), officially Viet Nam Cong San [Vietnamese Communists], People's Liberation Armed Forces in South Vietnam. The term was originally applied by Diem's regime to Communist troops (about 10,000) left in hideouts in South Vietnam after the Geneva Conference of 1954, following the French Indochina War (1946–54). Most Communist troops, according to the agreements, had withdrawn to North Vietnam. Supported and later directed by North Vietnam, the Viet Cong first tried subversive tactics to overthrow the South Vietnamese regime, then resorted to open warfare (see Vietnam War). They were subsequently reinforced by huge numbers of North Vietnamese troops infiltrating south, and aided in the reunification of Vietnam following the collapse of South Vietnam in 1975.