sentences:  On 9 September, the final assault to capture the heavily defended citadel was launched by the 147th and 258th Marine Brigades.The citadel was finally captured on 15 September.Meanwhile between 11 and 15 September the 2nd Marine Battalion advanced to the southern bank of the Thạch Hãn River, where they halted, exhausted and depleted by heavy casualties and unable to push on to Đông Hà.