 The ROK 23rd Regiment of the ROK 3rd Division was moved to block the advance of the three units at Uljin . The ROK forces mounted a series of delaying actions against the main North Korean force , which was significantly dispersed throughout the mountainous region and unable to muster its overwhelming strength . The ROK regiment was subsequently able to hold up the North Korean advance until July 5 . On July 10 , the 766th separated from the 5th Division and met an advance party of North Korean civilians in Uljin who had been sent to set up government in the area . From here , the 766th dispersed in small groups into the mountains . On July 13 it reached <unk> @-@ ri , 25 miles ( 40 km ) north of Yongdok . 
