Thursday's discovery of empty chemical warheads by U.N. inspectors in Iraq came as the United States was expressing growing impatience with Saddam Hussein and what is seen as his lack of active cooperation with the inspection process.

Officials here say U.S. experts have yet to determine the significance of Thursday's finding. But they say it came as no surprise, given the gaps in the weapons accounting Iraq gave the United Nations last month and what they say has been at best, superficial cooperation with the inspectors.

U.S. officials said soon after Iraq submitted the December 7 declaration that the document had serious omissions, including a lack of credible evidence that nearly 30,000 empty chemical warheads known to be in Iraqi hands in 1999 had been destroyed.

It is unclear if the warheads turned up by inspectors Thursday were part of those stockpiles, or had been newly-acquired. But administration officials say the finding adds to a body of evidence that Iraq is again resisting the inspections process. At an appearance in Scranton, Pennsylvania, President Bush renewed his warning that time is running out for a peaceful resolution of the situation.

"The world, overwhelmingly through the U.N. Security Council, said: Mr. Saddam Hussein, disarm for the name of peace. It's his choice to make. So far, the evidence hasn't been very good that he is disarming, and time is running out. At a point in time, the United States' patience will run out. In the name of peace, if he does not disarm, I will lead a 'coalition of the willing' to disarm Saddam Hussein," he said.

Thursday's discovery, at an ammunition storage area south of Baghdad, came as chief U.N. weapons inspector Hans Blix and International Atomic Energy Agency chief Mohammed ElBaradei prepared to go to Iraq for critical talks Sunday and Monday in advance of their January 27 report to the Security Council.

Bush administration officials have downplayed January 27 as a make-or-break point for possible military action. But they say it is an important juncture and that the inspections process should not be allowed to drag on.

At a briefing here, State Department spokesman Richard Boucher said the U.S. growing military buildup in the region would not dictate administration decisions, but he also said there is "no point in continuing forever" with the inspections exercise, if Iraq is not cooperating.

"If we continue to see Iraq's failures, to provide information, to account for things, to cooperate, then Security Council members will have to discuss that and consider it. The point I think is that by inspecting here, and inspecting there, and getting through a door there, we still haven't established a pattern of cooperation from Iraq. And the pattern of 'cheat and retreat' is emerging again as the one that Iraq is following," he said.

Spokesman Boucher said Doctors Blix and ElBaradei probably wouldn't have to go to Baghdad this weekend if Iraq had been forthcoming and provided inspectors with the information they need.

Mr. Blix said Thursday he would tell Iraqi authorities that only fuller cooperation with inspectors can avert war, though Mr. ElBaradei also said he will ask the Security Council to extend the inspections mandate by several more months.