The Korean peninsula had been occupied by Japan from 1910. On 9 August 1945, in the closing days of World War II, the Soviet Union declared war on Japan and advanced into Korea. Though the Soviet declaration of war had been agreed by the Allies at the Yalta Conference, the US government became concerned at the prospect of all of Korea falling under Soviet control. The US government therefore requested Soviet forces halt their advance at the 38th parallel north, leaving the south of the peninsula, including the capital, Seoul, to be occupied by the US. This was incorporated into General Order No. 1 to Japanese forces after the Surrender of Japan on 15 August. On 24 August, the Red Army entered Pyongyang and established a military government over Korea north of the parallel. American forces landed in the south on 8 September and established the United States Army Military Government in Korea.