 North of the US 9th Infantry and the battles in the Naktong Bulge and around Yongsan , the US 23d Infantry Regiment after daylight of September 1 was in a very precarious position . Its 1st Battalion had been driven from the river positions and isolated 3 miles ( 4 @.@ 8 km ) westward . Approximately 400 North Koreans now overran the regimental command post , compelling Freeman to withdraw it about 600 yards ( 550 m ) . There , 5 miles ( 8 @.@ 0 km ) northwest of Changnyong , the US 23rd Infantry Headquarters and Headquarters Company , miscellaneous regimental units , and regimental staff officers checked the North Koreans in a 3 @-@ hour fight . 
