On 22 March the 147th Marine Brigade at FSB Delta were still enduring fierce fighting with diminishing resources. PAVN troops had penetrated the base perimeter and late in the afternoon launched an assault supported by ten flame-throwing tanks. The Marines destroyed two tanks with M72 LAW rockets, a third was destroyed by mines and fourth by an airstrike. The Marines then abandoned Delta and withdrew towards the 258th Marine Brigade positions at FSB Hotel, however the PAVN intercepted the 147th Marines and a pitched battle ensued. The 147th Marines then successfully disengaged and by the morning of 23 March had arrived at FSB Hotel. 230 Marine wounded were evacuated and by nightfall the entire 147th Marine Brigade was evacuated by U.S. helicopters to Khe Sanh. 37 Marines were missing in the action while PAVN casualties were assessed to be heavy.