On 21 June, Kim Il-Sung revised his war plan to involve a general attack across the 38th Parallel, rather than a limited operation in the Ongjin Peninsula. Kim was concerned that South Korean agents had learned about the plans and that South Korean forces were strengthening their defenses. Stalin agreed to this change of plan.
On 25 November on the Korean western front, the PVA 13th Army Group attacked and overran the ROK II Corps at the Battle of the Ch'ongch'on River, and then inflicted heavy losses on the US 2nd Infantry Division on the UN forces' right flank.
X Corps managed to establish a defensive perimeter at the port city of Hungnam on 11 December and were able to evacuate by 24 December in order to reinforce the badly depleted US Eighth Army to the south.