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Korean War

Map of North and South Korea

The Korean War began on June 25, 1950, when North Korea (officially the Democratic People's Republic of Korea) launched a surprise attack on neighboring South Korea (officially the Republic of Korea). Against the expectations of the North Koreans and the Soviet Union, the United States immediately provided military support to South Korea, and the UN Security Council passed a resolution (UNSC Resolution 82) demanding a North Korean withdrawal to the 38th Parallel. Within days of the initial assault, UN forces under the leadership of General Douglas MacArthur began planning a large-scale counterassault, culminating in the Battle of Inchon in September 1950. In the months following the invasion at Inchon, UN troops forced the North Korean Army to retreat, capturing the capital of Pyongyang and reaching North Korea's northernmost border at the Yalu River. With secret backing from Moscow, in October and November 1950 hundreds of thousands of Chinese troops moved into North Korea and forced the South Korean and UN troops to retreat. By the summer of 1951, the conflict on the ground stalemated. While aerial bombing of North Korea and localized battles and skirmishes continued, the two sides exchanged little territory over the next two years. The conflict ended with the signing of an armistice on July 27, 1953. It preserved the prewar geographic division of Korea, keeping North Korean and South Korean troops on active alert on opposite sides of the Military Demarcation Line.