North Korea invaded South Korea in 1950 with support from the Soviet Union. In response, South Korea requested assistance from the United Nations, who sent troops from 15 countries to push back North Korean forces almost to the Chinese border. However, China then sent 300,000 troops in support of North Korea, recapturing the capital city of Seoul. U.S. General Douglas MacArthur proposed using nuclear weapons but was removed from command after calling for expanding the war against China. An armistice was finally signed in 1953, ending direct fighting but leaving the peninsula divided.