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,
United States in the Korean War were destroyed. The US had lost the battle, revealing that the mere sight of US troops would not reverse the military balance in Korea. By early August, the North Korean troops had pushed back the US and South Korean troops all the way to Naktong River, which is located about thirty miles from Pusan. The two weeks of fighting following this resulted in the most casualties of US troops than any other equivalent period of this war. However, during this time the US pushed supplies and personnel to Korea and by the end of July South Koreans and US troops