U.S. Ambassador to Japan Howard Baker on Tuesday urged Prime Minister Junichiro Koizumi to address U.S. concerns that North Korea is developing weapons of mass destruction on his landmark trip to Pyongyang next week.

This will likely be the message U.S. President George W. Bush delivers to Koizumi when the two leaders meet in New York on Thursday before Koizumi's historic meeting with North Korean leader Kim Jong Il, Baker told a news conference at the Foreign Correspondents' Club of Japan.

"It would be our hope that the North Koreans will renounce their commitment to terrorism, to their development of weapons of mass destruction, to their repression of their people," Baker said.

Baker hailed Koizumi's decision to visit Pyongyang as "courageous" leadership but voiced reservations he would actually be able to succeed in extracting promises from the communist leader. "Possibilities are endless, but the promises are not without limitations," he said. "I have no idea what the results are."

Regarding speculation over U.S. plans to attack Iraq, the ambassador repeated that Washington has made no specific request for help from Japan. But he stressed that the U.S. believes Japan would back U.S. action once President Bush makes a decision.

"My guess is that Japan will decide that it will be a friend (of the U.S.) in any efforts that the U.S. may initiate," Baker said.