Senior U.S. administration officials held secret talks in North Korea on at least three occasions in 2011 and 2012, The Asahi Shimbun has learned.
Although the visits had potential implications for Japan, Washington did not inform its security partner at the time and only informally confirmed one of them when the Japanese side pressed, government and other sources in Japan, South Korea and the United States said.
The U.S. State Department even warned the Foreign Ministry against making further inquiries, saying they would harm bilateral relations, the sources said.
U.S. military planes flew from an air base in Guam to Pyongyang and back on April 7, 2012, and again on a longer visit lasting from Aug. 18-20, the sources said.