Japan annexed Korea as part of its empire in 1910 after it won the Sino-Japanese War in 1894-95 and Russo-Japanese War in 1904-05. Korea had been under the Japanese control until the end of World War II in 1945. The surrender of Japan in August 1945 led to the immediate division of Korea into two occupation zones, with the United States administering the southern half of the peninsula and the Soviet Union taking over the area to the north of the 38th parallel. This division was meant to be temporary until the United States, United Kingdom, the Soviet Union, and China could arrange a trusteeship administration. But initial hopes for a unified Korea quickly evaporated as the politics of the Cold War and domestic opposition to the trusteeship plan resulted in the 1948 establishment of two separate nations: the Republic of Korea in the South and the Democratic People's Republic of Korea in the north. Both governments claimed the peninsula, and relations became strained. After several border clashes, North Korean troops invaded the south in June 1950, which started the Korean War that lasted for three years. An armistice ended the war in 1953, but a permanent peace treaty has never been signed.
After the Korean War, North Korea adopted a policy of diplomatic and economic self-reliance as a check against outside influence. As such, North Korea is one of the world's most centrally-planned and isolated economies. Decades of the rigid state-controlled system and adherence to the philosophy of self-reliance have destroyed the country’s economy, and large scale military spending has eaten into resources needed for investment and consumer industries. The country suffers from chronic food shortages caused by natural disasters and economic mismanagement. Since the mid-1990s, North Korea has been dependent on foreign aid to feed millions of its people. In July 2006, North Korea test fired a number of short-range missiles. Diplomatic efforts aimed to rein in North Korea's nuclear ambitions, and North Korea agreed to abandon its nuclear ambitions in return for aid. It shut down the Yongbyon nuclear reactor in July 2007. But tensions between North Korea and the rest of the world have again increased steadily since late 2008. In April 2009 North Korea walked out of international talks aimed at ending its nuclear activities. The following month, the country carried out its second underground nuclear test. From that time to date, North Korea's controversial nuclear program and its leadership by the highly flamboyant and volatile Kim Jong-il have been cause for concern as regards global security.