 By July 28 , the division was still embroiled in this fight and the 766th bypassed it and moved toward <unk> on the left flank of the city . However the 766th had suffered significant setbacks at Yongdok , with substantial losses due to American and British naval artillery fire . Once it arrived in the area , it met heavier resistance from South Korean police and militia operating in armored vehicles . With air support , they offered the heaviest resistance the unit had faced thus far . With the support of only one of the 5th Division 's regiments , the 766th was unable to sustain its advance , and had to pull back by the 29th . Movement from the ROK Capital Division prevented the 766th Regiment from infiltrating further into the mountains . ROK cavalry and civilian police then began isolated <unk> against the 766th . These forces included special counter @-@ guerrilla units targeting the 766th and <unk> its tactics . South Korean troops halted the advance of the North Koreans again around the end of the month thanks to increased reinforcements and support closer to the Pusan Perimeter logistics network . 
