The United States has told Japan it will keep it under its "nuclear umbrella" even after it gives North Korea security assurances in exchange for Pyongyang abandoning its nuclear arms program.
Washington's promise to Japan, made in September, is expected to infuriate North Korea, despite Pyongyang's positive response to U.S. President George W. Bush's earlier proposal of a multilateral written security assurance, analysts said.
It may also affect the process of preparing the security assurance document, sources familiar with Japan-U.S. relations said Thursday.
Japan had been concerned that if security assurances were given to North Korea, the U.S. would be unable to take appropriate military measures against the country if it attacked Japan.