killed, 411 wounded and 57 missing American soldiers, and 43 killed, 102 wounded South Korean soldiers. The Chinese People's Volunteer Army (PVA) entered the war on the side of North Korea, making their first attacks in late October. The 7th Infantry Division began landing at Wonsan on 26 October, and Iwon on 29 October. The landing was delayed due to the presence of mines, and by the time X Corps came ashore, ROK forces moving overland had already occupied the ports. The division advanced to Hyesanjin, on the China–North Korea border by the Yalu River, one of the northernmost advances for UN soldiers of the war. Much of X Corps followed behind. On 21 November, the 17th Infantry reached the banks of the Yalu River. The advance went quickly for the 7th Infantry Division and ROK troops while the Marines were not able to advance as quickly. The division halted its advance until 24 November while other units of the Eighth Army's IX Corps and ROK II Corps caught up and supply lines were established. During this time, the 7th Division's regiments were spread out on the front line. The 31st Infantry Regiment remained at the Chosin Reservoir with the 1st Marine Division while the 32nd and 17th Infantry Regiments were much further to the northeast, closer to ROK I Corps. It was during this time that the division was served by a new type of unit, the 1st Mobile Army Surgical Hospital (M.A.S.H.). Chinese intervention The UN forces renewed their offensive on 24 November before being stopped by the PVA Second Phase Offensive starting on 25 November with attacks on Eighth Army's IX Corps and ROK II Corps in the west and X Corps in the east. X Corps found itself under attack from the PVA 20th, 26th and 27th Field Armies, commanding a total of 12 divisions. During the furious action that followed, the 7th Infantry Division's spread out regiments were unable to resist the overwhelming PVA forces. Three of the division's infantry battalions were attacked from all sides the next day. 1st Battalion, 32nd Infantry (nicknamed Task Force Faith) was trapped with two other battalions by the PVA 80th and 81st Divisions from the 27th Field Army. In the subsequent Battle of Chosin Reservoir, the three battalions were destroyed by overwhelming PVA forces suffering over 2,000 casualties. The 31st Infantry suffered heavy casualties trying to fight back