<P> With the onset of the Cold War , negotiations between the United States and the Soviet Union failed to lead to an independent , unified Korea . In 1948 , UN-supervised elections were held in the US - occupied south only . This led to the establishment of the Republic of Korea in South Korea , which was promptly followed by the establishment of the Democratic People 's Republic of Korea in North Korea . The United States supported the South , the Soviet Union supported the North , and each government claimed sovereignty over the whole Korean peninsula . </P>
<P> With the onset of the Cold War , negotiations between the United States and the Soviet Union failed to lead to an independent , unified Korea . In 1948 , UN-supervised elections were held in the US - occupied south only . This led to the establishment of the Republic of Korea in South Korea , which was promptly followed by the establishment of the Democratic People 's Republic of Korea in North Korea . The United States supported the South , the Soviet Union supported the North , and each government claimed sovereignty over the whole Korean peninsula . </P>
when did north and south korea become separate countries
when did north and south korea become separate countries
1948
1948