Korean War has since been patrolled by the KPA and ROKA, United States, and Joint UN Commands. The Demilitarized Zone runs northeast of the 38th parallel; to the south, it travels west. The old Korean capital city of Kaesong, site of the armistice negotiations, originally was in pre-war South Korea, but now is part of North Korea. The United Nations Command, supported by the United States, the North Korean People's Army, and the Chinese People's Volunteers, signed the Armistice Agreement on 27 July 1953 to end the fighting. The Armistice also called upon the governments of South Korea, North Korea, China and
Soviet Union in the Korean War pilots flying MiG-15 jets participated in battles around the Yalu River Valley on the Chinese-Korean border in the area known as "Mig Alley" and in operations against UN "trainbusting" attacks in Northern Korea, with considerable success. The lack of a shared language between Soviet, Chinese and North Korean pilots frequently led to incidences of friendly fire as other MiG fighters were mistaken for American F-86 Sabre jets and shot down. The MiG-15 was a jet aircraft, supplied in large numbers to Chinese and North Korean forces during the war by the Soviet Union. Owing to their modern design (they were