A female North Korean soldier guards the banks of the Yalu River near the Chongsong county of North Korea opposite the Chinese border town of Hekou, northeastern China's Liaoning province May 31, 2009. U.S. Defense Secretary Robert Gates said on Saturday the United States would not accept a nuclear-armed North Korea and he warned Pyongyang against transferring nuclear material overseas. REUTERS/Jason Lee (NORTH KOREA POLITICS MILITARY IMAGES OF THE DAY)