In the 8 kilometers area between the Cam Lo Bridge and Dong Ha Bridge, the NVA were supported by two tank regiments of 150 Soviet T-54 and PT-76 tanks, 75 tracked anti-aircraft vehicles, an artillery regiment of 47 towed 130mm guns, and the largest concentration of anti-aircraft weaponry of the entire war, including the advanced SA-2 surface-to-air missile (SAM).