 Over the next week the 766th Regiment and the KPA 's 5th Division continued in a slow advance south as it met increasing South Korean resistance . United Nations air support began to increase , slowing the advance further . The force continued to occupy the eastern flank , and by July 24 it was advancing from the <unk> @-@ <unk> region and approaching <unk> . On its flank was the KPA 's 12th Division . Progress halted as UN aerial and naval bombardment made movement more difficult . At the same time the North Korean units ' supply lines were stretched thin and began to break down , forcing them to <unk> South Korean civilians to carry supplies . 
