The warhead of a long-range missile test-fired by North Korea was found in the U.S. state of Alaska, a report to the National Assembly revealed yesterday. ``According to a U.S. document, the last piece of a missile warhead fired by North Korea was found in Alaska,¡¯¡¯ former Japanese foreign minister Taro Nakayama was quoted as saying in the report. ``Washington, as well as Tokyo, has so far underrated Pyongyang¡¯s missile capabilities.¡¯¡¯