United Nations Service Medal Korea. This medal was authorized by the United Nations General Assembly on Dec. 12, 1950. The Department of Defense authorized it for the United States Armed Forces on Nov. 27, 1951. It is awarded to officers and enlisted men of the armed forces of the United States who participated in the action in Korea between June 27, 1950, and July 27, 1954. This medal is awarded for any period of time spent in combat.