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,
Korean War conflicts played more of a role in not deploying them than the threat of a possible nuclear exchange. When Eisenhower succeeded Truman in early 1953 he was similarly cautious about using nuclear weapons in Korea, including for diplomatic purposes to encourage progress in ongoing truce discussions. The administration prepared contingency plans to use them against China, but like Truman, the new president feared doing so would result in Soviet attacks on Japan. The war ended as it began, without U.S. nuclear weapons deployed near battle. There were numerous atrocities and massacres of civilians throughout the Korean war committed by both