The Battle of An Lão occurred after the Viet Cong (VC) captured the district headquarters of An Lão, Binh Dinh, about 300 miles from Saigon. Viet Cong rebels launched an early morning surprise attack, attack squads scaling the fence and lobbing grenades to disable the Army of the Republic of Vietnam (ARVN) machine gun positions ringing the base. A second wave of attackers infiltrated the base and took control. The Viet Cong were successful in repeatedly beating back large numbers of counterattacking ARVN troops, who rushed in by jeep and APC. Inserted by helicopter, a U.S. scout team engaged the VC at range of only 100 meters, inflicting significant casualties but proving unable to break the rebel grip on the headquarters.
The strength of the VC attack in northern Binh Dinh Province indicated the changing tactics of the VC, who were prepared to switch from small-scale guerrilla actions to mobile warfare.