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,
Soviet Union in the Korean War Soviet Union in the Korean War Though not officially belligerent during the Korean War (1950–1953), the Soviet Union played a significant, covert role in the conflict. It provided material and medical services, as well as Soviet pilots and aircraft, most notably MiG 15 fighter jets, to aid the North Korean-Chinese forces against the United Nations Forces. The Soviet 25th Army took part in the Soviet advance into northern Korea immediately after World War II had ended, and was headquartered at Pyongyang for a period. Like the American forces in the south, Soviet troops remained in Korea after the end of