Korean War two years of fighting became a war of attrition, with the front line close to the 38th parallel. The war in the air, however, was never a stalemate. North Korea was subject to a massive bombing campaign. Jet fighters confronted each other in air-to-air combat for the first time in history, and Soviet pilots covertly flew in defense of their communist allies. The fighting ended on 27 July 1953, when an armistice was signed. The agreement created the Korean Demilitarized Zone to separate North and South Korea, and allowed the return of prisoners. However, no peace treaty was ever signed,
Australia in the Korean War to as the Fifth Phase Offensive, with the intention of recapturing Seoul. The Chinese launched a major assault between 22 and 25 April that resulted in a victory in the Battle of the Imjin River. At the same time, the UN repelled Chinese forces at Kapyong. Chinese forces of the 118th Division attacked the Kapyong Valley in force, and pushed South Korean and New Zealand troops into retreat. Under heavy pressure, the Korean 6th Division broke, and the line collapsed. American and South Korean men poured through a gap under protective covering fire from Australians who were holding their section