In the days before the battle, Hoang anticipated a major attack from the South Vietnamese government, as VC intelligence agents in Dinh Tuong had reported the arrival of 71 truckloads of ammunition and other supplies from Saigon, about to the northeast. In addition, with information provided by Pham Xuan An, a well-connected journalist and undercover VC agent in Saigon, Hoang's soldiers conducted last-minute anti-helicopter and anti-M113 training by studying US weaponry and South Vietnamese plans and manuals. Furthermore, using radios captured from the ARVN, the VC was able to intercept news of the attack due to unencoded radio communications from the ARVN. The VC also took full advantage of the local terrain by taking up positions in Ap Tan Thoi in the north, along a tree-lined creek in the southeast, and Ap Bac in the south. Their positions were well-concealed by trees and shrubs, which made them difficult to see from the air and provided good protection from heavy weaponry. To the south and west of Ap Bac, the VC dug a series of foxholes in front of an irrigation dike, which afforded them an unobstructed field of fire in the surrounding rice fields. The foxholes were deep enough for one man to stand up, or big enough to accommodate a two-man machine gun crew. Behind the foxhole line, the irrigation dike enabled VC units to communicate with each other. In short, the VC enjoyed a great advantage over any attacking force.