Northern Limit Line mainland portion reverted to North Korean control, while the islands remained a part of South Korea despite their close proximity. The line extends into the sea from the Military Demarcation Line (MDL), and consists of straight line segments between 12 approximate channel midpoints, extended in an arc to prevent egress between both sides. On its western end the line extends out along the 38th parallel to the median line between Korea and China. The 1953 Armistice Agreement, which was signed by both North Korea and the United Nations Command (UNC), ended the Korean War and specified that the five islands
Soviet Union in the Korean War the United States and its allies elsewhere, which could have led to a nuclear war. By officially denying its participation, the Soviets prevented the Korean War from escalating. Participation on the North Korean side was also contrary to the UN Security Council Resolution 84 by which the Soviet Union was technically bound. Along with several "Eastern Block" countries (notably Czechoslovakia), the Soviet Union sent over 20 doctors to Korea to aid Communist forces there, similar to Indian, Italian, Norwegian, Danish and Swedish medical detachments in Southern Korea who did not have military force engaged, but merely offered humanitarian support instead.