The attack tapered off with the coming of daylight , but that night it resumed . The North Koreans struck repeatedly at the defense line . This time they continued the fighting into the daylight hours of 9 September . The Air Force then concentrated strong air support over the regimental perimeter to aid the ground troops . Casualties came to the aid stations from the infantry companies in an almost steady stream during the morning . All available men from Headquarters Company and special units were formed into squads and put into the fight at the most critical points . At one time , the regimental reserve was down to six men . When the attack finally ceased shortly after 12 : 00 the 23rd Regiment had an estimated combat efficiency of only 38 percent .