South Korea–United States relations
Following Japanese surrender at the end of the Second World War, the Allied Powers divided the Korean peninsula along the 38th Parallel with two occupation zones with the United States in the south, and the Soviet Union in the north that would later become North Korea. On August 15, 1948, the southern half of Korea declared independence as the Republic of Korea with Syngman Rhee as president. The United States recognized the Republic of Korea as an independent state on January 1, 1949 and diplomatic relations between two countries were established on March 25 in the following year.
Cross-border skirmishes and raids at the 38th Parallel escalated into open warfare when the North Korean forces invaded South Korea on June 25, 1950. The Korean War broke out when North Korea invaded South Korea. In response, 16 member countries of the United Nations, including the United States, came to the defense of South Korea. It was the first significant armed conflict of the Cold War with extensive deployment of American and other troops.
History of North Korea
During August, People's Committees sprang up across Korea, affiliated with the Committee for the Preparation of Korean Independence, which in September founded the People's Republic of Korea. When Soviet troops entered Pyongyang, they found a local People's Committee established there, led by veteran Christian nationalist Cho Man-sik. Unlike their American counterparts, the Soviet authorities recognized and worked with the People's Committees. By some accounts, Cho Man-sik was the Soviet government's first choice to lead North Korea.