Iraq's arms declaration is incomplete, its scientists aren't fully cooperating with inspections and Baghdad is obstructing the use of a U-2 plane that could be helpful in the hunt for weapons of mass destruction, inspectors are expected to tell the Security Council in a toughly-worded report Monday.

After two months on the job, the chief weapons inspectors, who will deliver their assessments to the Security Council Monday at 10:30 a.m. EST, won't be able to confirm claims by the Bush administration that Iraq is rearming, according to U.N. officials, who spoke on condition of anonymity.

Still, with all the open questions, the reports by Hans Blix and Mohamed ElBaradei will be key to Washington's efforts to bolster international support for a war on Iraq and to efforts by skeptics to avert one.

By mid-afternoon Sunday, Blix had written a toughly-worded 16-page report that he will deliver as a speech during the public portion of Monday's council meeting. "I have been working very hard and very carefully on the details," he told The Associated Press.

He wouldn't discuss the contents because of "sensitivities and expectations," surrounding the report.

U.S. Ambassador John Negroponte is expected to respond to the inspectors' reports once Monday's session moves behind closed-doors. An administration official, who spoke on condition of anonymity, said the ambassador would focus more on Iraq's obligations than on the inspectors' findings. "He will remind the council that they all agreed in November that this would be Iraq's last opportunity to comply and that two months is more than enough time to test Saddam's intentions to cooperate," the official told AP.

The inspectors still don't know what happened to Iraq's stockpiles of biological and chemical weapons or how much time they have left to find the answers.

Still, ElBaradei, who heads the International Atomic Energy Agency, intends to make the case for more time.

"We're just in mid-course and we still need to exhaust the option of inspections before we think of any alternatives," ElBaradei told AP upon his arrival to New York from Vienna Sunday. "We still need more time and that depends obviously on how intensive our work is and how cooperative Iraq is."

According to Security Council Resolution 1441, crafted by the Bush administration and adopted in November, inspectors don't need to prove Iraq is rearming.

Any false statements or omissions in Iraq's arms declaration, coupled with a failure to comply with and cooperate fully in the implementation of the resolution, would place Baghdad in "material breach" of its obligations -- a finding that could open the door for war.

For the Bush administration, that has already happened and time is now running out for Saddam to disarm through inspections. In Davos, Switzerland Sunday, Secretary of State Colin Powell said he believed the inspections had run their course, though he did not explicitly call for their end. He said that as a result of Iraq's lack of cooperation, he had lost faith in the ability of inspectors to fulfill their mission.

Most of the Security Council believes that's a determination they must make based on the inspectors' assessments. At the U.N. headquarters, Blix would not comment on Powell's speech.

While there is general agreement that Iraq hasn't been fully honest in its declaration and that it could be cooperating better with inspectors, the absence of a smoking gun or cries for help from Blix and ElBaradei have led powerful council members such as France, Germany and Russia to argue against military intervention and in favor of more time for peaceful disarmament.

While Blix and ElBaradei have criticized Iraq over the past 60 days, they have also praised the access inspectors were given at hundreds of sites, including presidential palaces, as well as Iraq's cooperation in the areas of logistics and supplies.

Blix's report will focus on what his inspectors at the U.N. Monitoring, Verification and Inspection Commission have -- and haven't -- learned about Iraq's biological, chemical and missile programs.

So far, inspectors have discovered thousands of pertinent documents hidden in the home of an Iraqi scientist, at least 16 empty and undeclared chemical warheads and have said that Iraq illegally imported parts for its missile program. Based on one of the few new documents Iraq produced last fall, inspectors are now convinced there are an additional 6,000 chemical weapons unaccounted for.

But what inspectors have learned is far less than they had hoped to know by now.

Unanswered is whether Iraq really destroyed all of its deadly chemical and biological agents, such as VX and anthrax, which it managed to weaponize more than a decade ago on the eve of the 1991 Persian Gulf War.

Iraq's 12,000-page arms declaration has been of little help. Two weeks after he received the dossier in December, Blix slammed the Iraqis for submitting a report filled with inconsistencies, contradictions and old material.

During a meeting with Iraqi officials in Baghdad last week, Blix pressed for fresh evidence and answers to long outstanding questions on their weapons of mass destruction.

But that information hasn't been forthcoming.

Neither Blix not ElBaradei's teams have been able to privately interview Iraqi scientists believed to have the best information about Iraq's weapons programs. And the Iraqis are blocking inspectors from conducting U-2 reconnaissance flights.

Still, the picture emerging on Iraq's nuclear program seems to be slightly more favorable.

ElBaradei's spokesman said Iraq would get a "satisfactory" grade for its response to questions and requests for information from the nuclear inspectors.

His teams seem convinced that aluminum tubes the Iraqis tried to purchase were meant for artillery rockets they are allowed to have and not for enriching uranium for a nuclear program as the Bush administration claimed last fall.

And ElBaradei's oral report will include samples results revealing no indication of prohibited nuclear activities at sites inspected so far.

According to its weapons declaration, Iraq possessed all the necessary components for making nuclear weapons by the time the United States launched Operation Desert Storm to remove Saddam's troops from neighboring Kuwait.

Inspectors returned to Iraq in November, after a four-year absence, under the terms of Resolution 1441, which gave them broader authority but a tighter timetable for reporting to the Security Council.