The Bush administration has set the last week in January as the make- or-break point in the long standoff with Iraq, and is increasingly confident that by then it will have marshaled the evidence to convince the U.N. Security Council that Iraq is in violation of a U.N. resolution passed last month and to call for the use of force, officials said yesterday.

In a boost to the administration´s position, Hans Blix, the United Nations´ chief weapons inspector, plans to tell the Security Council today that Iraq failed to account fully for chemical and biological bombs and warheads it had assembled as well as materials it bought that could be used to produce more of them, U.N. and administration officials said.

After Blix offers his preliminary assessment in New York of the arms declaration that Iraq submitted 10 days ago, Secretary of State Colin L. Powell plans to deliver the administration´s reaction at the State Department in which he will declare that Iraq failed to fully disclose its past and present weapons programs, officials said.

In disclosing their plans, administration officials offered the clearest timetable to date of how they would like to see the inspections process brought to a head. They are pointing to Jan. 27, when Blix is scheduled to make his first substantive report to the Security Council on Iraq´s weapons declaration as well as the Baghdad government´s cooperation with inspectors already on the ground and in making Iraqi scientists involved in banned weapons programs available for interviews with U.N. officials.

That date falls within the late January to early February window U.S. military planners have said is the optimum moment to launch an invasion of Iraq.

Administration officials said that waiting until late January, rather than pushing for the Security Council to declare Iraq is in material breach of the resolution based on the arms declaration alone, will suffice to demonstrate the United States´ commitment to an international approach to ridding Iraq of its long-range missiles and chemical, biological and nuclear weapons programs.

The additional month, officials said, will also provide enough time to put together a case against Baghdad that Iraq will not be able to refute and even the most skeptical Security Council members will be unable to ignore. President Bush has made clear that he is prepared to move militarily against Iraq, with or without the United Nations, once the case has been made.

Powell said yesterday that other Security Council members share the U.S. assessment that the Iraqi declaration contains "troublesome" gaps and omissions. Once Blix and Mohamed El Baradei, head of the International Atomic Energy Agency, make their report today, he said, "we´ll . . . work with our partners in the Security Council to determine the way to go forward."

"We are not encouraged that [the Iraqis] have gotten the message or will cooperate, based on what we have seen so far in the declaration," Powell said. "But we will stay within the U.N. process."

White House spokesman Ari Fleischer said yesterday that "the United States will continue to be deliberative in this matter, but this was Saddam Hussein´s last chance." Noting Bush´s Sept. 12 speech to the U.N. General Assembly in which he challenged the world body to confront Iraq on its outlawed weapons programs, Fleischer said, "I think it´s important to allow a process that the president asked to begin, to take its course."

Senior administration officials have decided that the best way to hold the coalition of countries opposed to Iraq together is to permit the U.N. inspections to continue, officials said, because they are convinced Iraqi President Saddam Hussein will never disarm or provide the details being sought on his weapons programs. They also believe that once a system is worked out in which the U.N. inspectors begin making requests to interview Iraqi scientists or technicians outside the country, Hussein may block the process and create a direct material breach of the U.N. resolution. The resolution spelled out procedures for conducting the interviews.

In his presentation today, Blix plans to go down a list of unanswered questions raised in 1999 by the report of the previous U.N. weapons investigators, including Iraq´s failure to account for tons of the nerve agent VX and the precursor materials to make more, U.N. and U.S. officials said. He also plans to list 550 artillery shells with mustard gas, 157 bombs that at one time were filled with either anthrax or other biological agents, and a number of warheads that showed traces of VX.

The Swedish diplomat is particularly concerned with Iraq´s failure to deal with these matters because he and El Baradei had specifically warned Iraqi officials in Baghdad last month that they should go through their records on these weapons. "They at least expected Saddam Hussein would toss them a bone and instead they didn´t even get a crumb," one U.N. official said yesterday.

In 1995, after denying in 1991 it had any biological warfare program, Iraq admitted it had produced 166 R-400 bombs that were filled with biological agents including anthrax spores. It also said that during the Persian Gulf War in 1991 the bombs were taken from military facilities and buried at two locations, one along the Euphrates River.

When the war ended, the Iraqis said they destroyed all the bombs by blowing them up at two separate sites. While they described in detail the manner of the destruction, they never produced documents on who ordered or carried out the destruction.

A senior Iraqi official recently told the U.N. inspectors that it was a great mistake to have "obliterated" records of the nation´s biological weapons program, officials said.

British Foreign Secretary Jack Straw joined Powell and Blix yesterday in questioning the Iraq report. "There are some obvious omissions," Straw said, citing failing to include "large quantities of nerve agent, chemical precursors and munitions" that had been disclosed in the 1990s. "It seems that Saddam Hussein has decided to continue the pretense that Iraq has had no WMD [weapons of mass destruction] program since [the previous U.N. inspectors] left in 1998," he said.

The State Department´s top liaison with the U.N. inspection agencies, John S. Wolf, the assistant secretary of state for nonproliferation, made a similar case in meetings in Washington yesterday with some of the 10 nonpermanent members of the Security Council before he left for New York last night to meet with El Baradei.

French Defense Minister Michele Alliot-Marie, on a trip to Qatar in the Persian Gulf region, told reporters that judgment on Iraq´s declaration should await results from the U.N. arms inspectors. "The ball is now in the court of the inspectors and it is their duty to evaluate the document and check on whether Iraq has any weapons of mass destruction," she said.

At the United Nations, Syria´s deputy U.N. ambassador, Fayssal Mekdad, returned the excised copy of the Iraqi arms declaration given to his government. "Either we take a full copy or we don´t take anything," he said.

At the Bush administration´s request, the Security Council´s current president, Alfonso Valdivieso of Colombia, decided that the 10 nonpermanent members of the body should receive excised copies of the declaration on the grounds that some material could contain information on building weapons of mass destruction.

As a result, the U.N. inspectors removed almost 8,500 pages of the original 12,000 supplied by Baghdad in the copies turned over to the nonpermanent members, while only the council´s five permanent members -- the United States, Britain, France, Russia and China -- received the full copy. Staff writer Colum Lynch at the United Nations contributed to this report. (© 2002 The Washington Post Company 12/19/02)