Washington ? After completing a review of Iraq’s report on its weapons programs, the Bush administration Thursday declared Iraq to be in “material breach” of a United Nations resolution ordering it to disarm, but the White House is putting off for several weeks a decision on whether to push for the use of military force.

U.N. weapons inspectors said Iraq’s 12,000-page report on its weapons programs included little new information and no proof that it destroyed the chemical and biological agents that U.N. inspectors had confirmed it possessed before leaving Iraq under duress in 1998.

Secretary of State Colin Powell said unless the Iraqis reverse their ways and acknowledge that they have chemical, biological and nuclear weapons programs, “we’re not going to find a peaceful solution to this problem.”

Powell’s statement was the United States’ formal response to the Iraqi declaration that was required in last month’s U.N. resolution. It had been widely expected that the United States would be critical of the document, but Powell’s comments were closely watched by allies who fear the administration might use the report as a trigger for military action.

The secretary of state made his comments shortly after Hans Blix, the chief U.N. arms inspector, and Mohamed ElBaradei, director of the International Atomic Energy Agency, told U.N. member nations that a preliminary review of Iraq’s weapons declaration indicated that it still may be hiding anthrax and other deadly agents.

U.S. officials said Iraq also has not accounted for stockpiles of mustard, sarin and VX gases, nor its long-range missile technologies.

Bush administration officials said they found enough omissions in the report to declare Iraq in “material breach” of the U.N. resolution requiring the “accurate, full and complete” disclosure of its chemical, biological and nuclear weapons.

The administration had insisted that such a breach would be grounds for war — or what the U.N. resolution refers to as “serious consequences” — but U.S. officials said Thursday that they would allow the inspections to continue for several more weeks, putting off a decision on whether to attack Iraq until late January.

“Iraq’s noncompliance and defiance of the international community has brought it closer to the day when it will have to face these consequences,” Powell said. “The world is still waiting for Iraq to comply with its obligations. The world will not wait forever.”

Bush said nothing publicly about Iraq Thursday.

The United States is demanding that U.N. arms inspectors, who in three weeks have found no evidence of Iraqi weapons of mass destruction, intensify their searches. The U.S. also wants a more assertive effort made to gain access to Iraqi scientists who have worked on weapons programs, a source of information the Bush administration believes would be more accurate and detailed than inspections alone.

Blix’s tone was far more muted than Powell’s.

“Iraq has been opening doors to us,” Blix said. “Iraq has been giving us immediate access to sites.”

On the process overall, Blix added, “We are not optimistic or pessimistic. We are trying to provide objective assessment.”

A number of U.S. allies, including France and Russia, warned Thursday that it is up to the U.N. Security Council, not the United States alone, to determine if Iraq is in material breach of the resolution. They also insisted that no arbitrary deadlines be set for the weapons inspectors.

Even Britain, the United States’ most dependable ally on the issue of Iraq, declined to declare Iraq in material breach of the resolution.

Iraq claims in its voluminous weapons report that it does not possess any chemical, biological or nuclear weapons and is not trying to develop them.

Amir Al-Saadi, science adviser to Iraqi President Saddam Hussein, said the United States was attacking Iraq’s weapons report out of desperation.

The United States, he said, “is worried because there is nothing that they can pin on us. All their statements were mere allegations, not supported by evidence.”