Border clashes soon broke out between the two Koreas, each of which claimed sovereignty over the entire peninsula.ĭid you know? After he was removed from command by Truman, General MacArthur gave a dramatic televised address before a joint session of Congress in April 1951 in which he criticized Truman's Korean policy. The arrangement was intended as temporary however, after plans to establish a national government failed, two separate nations formed in 1948: the Communist-backed Democratic People’s Republic of Korea ( North Korea) and the Western-aligned Republic of Korea ( South Korea). Korea was divided into two occupations zones, with the Soviet Union administering the area north of the 38th parallel and the United States administering the area south of the 38th parallel. After Japan was defeated by the Allies in World War II (1939-45), it lost control of Korea, which it had ruled as a colony since 1910.