 The 5th Division and the two other units began advancing south slowly and cautiously, sending strong reconnaissance parties into the mountains to ensure they would not be threatened from the rear.However, this more cautious advance began to give the South Koreans valuable time to build up further south.By June 28, the 766th had infiltrated into Taebaek-san from Uljin and was moving toward Ilwolsan, Yongyang and Cheongsong in order to block communications between Daegu and Busan, where United States Army forces were landing in an attempt to support the collapsing ROK Army.