The origins of the Korean War can be traced back to the end of the Second World War, when the Allies were entrusted with control of the Korean peninsula following 35 years of Japanese occupation. The United States and the Soviet Union accepted mutual responsibility for the country, with the Soviets taking control of the country to the north of the 38th Parallel and the Americans taking the south. Over the next few years, the Soviet Union fostered a communist government under Kim Il-Sung and the US supported the provisional government in the south, headed by Syngman Rhee. By 1950 tensions between the two zones had risen to the point that two increasingly hostile armies had built up along the 38th Parallel.