The Battle of Ấp Bắc was a major battle fought on 2 January 1963 during the Vietnam War in Định Tường Province, South Vietnam. On 28 December 1962, US intelligence detected the presence of a radio transmitter along with a sizable force of Viet Cong (VC) soldiers, reported to number around 120, in the hamlet of Ap Tan Thoi in Dinh Tuong Province, home of the Army of the Republic of South Vietnam (ARVN) 7th Infantry Division. The South Vietnamese and their US advisers planned to attack Ap Tan Thoi from three directions to destroy the VC force by using two provincial Civil Guard battalions and elements of the 11th Infantry Regiment, ARVN 7th Infantry Division. The infantry units would be supported by artillery, M113 armored personnel carriers (APCs), and helicopters. However, Viet Cong forces anticipated a major attack from the South Vietnamese government from a variety of sources including movement of supplies, an undercover VC agent, and decoded radio communications from the ARVN. Accordingly, the VC prepared for an attack by US and South Vietnamese forces.