<P> 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 . </P> <P> 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 the war to rebuild the country . </P>

Who did the soviet union support in the korean war