Explain how Korea came to be divided into two separate states during the period 1945-53?

The feud between the rulers of North and South Korea existed from a very long time. After the occupation of Korea during the Russo-Japanese War. Witnessing the situation, the countries US, UK and China had committed that a united, independent Korea would be created. But since Japan got defeated as early as in 1945, the commitment could not be fulfilled. The problem arose when Russia declared war on Japan in 1945. Russia had an ambition to gain influence in Korea. Since they were in Manchuria, close to North Korea, they moved in there and the forces started working with the Korean communists and nationalists. They proclaimed Korean People’s Republic and declared Kim II sung as the leader. He soon started giving out his own version of Marxism-Leninism in the new state.
Seeing the increase Russian influence, US quickly entered the south of Korea. It was the Americans who first proposed the division of Korea along the 38th parallel. There Dr Syngman Rhee emerged as the leader. Now he was an anti communist nationalist leader. So, he strived to build a united Korea free of communism. In response Stalin sent huge troops to North Korea to help it defend any attack from the south. Although Stalin withdrew Soviet troops in 1948, the People’s Democratic Party was proclaimed as leading and North Korea became an independent state, which was given official diplomatic recognition by China, USSR and communist nations of eastern Europe. Although both USA and USSR and China wanted a pro Western and communist government respectively, none of them interfered. They handed over the issue to the United Nations which took the first stance of organizing elections for the whole country. But north did not agree to it and held its own elections. South did hold the elctions according to UN. Both the sides chose their own leader and north launched an attack on south. Later a peace agreement was made in  but 4 million Koreans had lost their lives and the two remained divided into mutually suspicious states.