A U.S. diplomat failed Wednesday to win the release of an American pilot held in North Korea. An angry President Clinton denied the pilot was on a spy mission and said the North had no reason to hold him.

Army pilot Bobby Hall was captured after his U.S. Army OH-58C helicopter went down Dec. 17 in North Korean territory. Fellow Chief Warrant Officer David Hilemon died. His body was returned Thursday.Wednesday, Clinton denied the North's charges that Hall was a spy and insisted that the helicopter wandered into communist territory by accident. "There is no reason for his detention," he said.

But the president stopped short of threatening to undo the recent U.S.-North Korea nuclear accord.

Thomas Hubbard, a deputy assistant secretary of state who has negotiated with North Korea before, traveled there Wednesday to try to defuse an already difficult international incident that has taken a sudden turn for the worse.

Rep. Lee Hamilton, the outgoing chairman of the House Foreign Relations Committee, said he was told the talks between Hubbard and the North Koreans "were not very satisfactory."

"The latest information I have simply was that his initial meetings did not meet with success, and that the next step was military talks with regard to the incident itself," Hamilton, D-Ind., told Fox TV.

The United States, he said, is having a hard time convincing the North Koreans that the helicopter was not on a spy mission.

When Hilemon's body was returned under a deal negotiated by U.S. Rep. Bill Richardson, D-N.M., there were hopes Hall would be released by Christmas.

But as the holiday came and went, concerns grew. Then on Tuesday, North Korea accused Hall of spying and demanded that Washington apologize.