At 03:00 on 21 March the PAVN 2nd Division attacked the 2nd and 4th Battalions, 2nd Infantry Regiment losing 245 killed and 52 B-40/1s, 12 mortars, eight flamethrowers, nine 12.7mm machine guns and 65 AK-47s captured for ARVN losses of 37 killed and 15 missing. The two battalions were evacuated by helicopter later that day. The headquarters 1st Airborne Brigade, the 5th Airborne Battalion and artillery units at FSB Alpha were evacuated south and FSBs Alpha and Delta 1 were closed and all ARVN forces pulled back to FSB Bravo (). In the south the PAVN 29th and 803rd Regiments attacked FSB Delta at dawn starting with an intense artillery bombardment. The South Vietnamese responded with 175mm fire and the USAF conducted 13 tactical airstrikes and one B-52 strike which reportedly destroyed a PAVN battalion. The Marines at Delta held the base having lost 85 killed and 238 wounded, while PAVN losses were over 600 killed and five captured and an estimated 260 weapons captured. A resupply mission was able to support the base and evacuate wounded but one U.S. UH-1H was shot down. The PAVN continued their attacks on FSB Bravo with the 11th Armored Cavalry Squadron and 8th Airborne suffering 100 casualties and damage to four M41s and 13 APCs. A sapper attack on Vandegrift Combat Base destroyed 10,000 gallons of aviation fuel. U.S. air support during the day included 788 helicopter gunship sorties, 157 tactical airstrikes which destroyed 37 PAVN vehicles and one gun and 11 B-52 strikes.