WASHINGTON - The Pentagon is preparing for a major call-up of National Guard and Reserves for a possible war against Iraq, a move that would bring the United States to a new level of readiness for military action, Defense Department officials said yesterday.

The size and timing of the mobilizations hinges heavily on Iraq's response to the United Nations resolution requiring Baghdad to disarm and the pace of the international arms inspections.

In what is likely to be only the first wave of new call-ups, the Pentagon is expected in the next several days to activate as many as 10,000 reservists, mainly military police units, for security duty here and abroad, officials said. They would join the 50,755 reservists now mobilized for the defense of the United States after Sept. 11 and for the war in Afghanistan.

But if President Bush orders an attack on Iraq, the Pentagon has plans to summon to active duty about as many reservists as it did during the Persian Gulf war in 1991, when about 265,000 members of the National Guard and Reserves were called up. No final decisions have been made on these larger mobilizations, officials said.

"Activating reserves is significant because it will affect every community in America, and it sends a signal that the president is serious," said a senior military official.

With the Pentagon pressing ahead with plans for a potential military conflict, the first week of U.N. weapons inspections in Iraq ended yesterday with furious Iraqi criticism.

Iraq denounced the inspectors for having insisted on a no-notice search of one of President Saddam Hussein's innumerable palaces Tuesday and also took the occasion to deny again, in some of the least ambiguous terms it has used, that it possesses any banned nuclear, chemical or biological arms.

"We have no weapons of mass destruction, absolutely no weapons of mass destruction," said Maj. Gen. Hussam Muhammad Amin, director of Iraq's National Monitoring Directorate, which was set up to work with U.N. inspectors.

He made the flat-out denial last night, in English, at the close of a 20-minute news conference that bristled with indignation at the "ridiculous" palace inspection and ascribed it to pressures from the United States, Britain and Israel.

Echoes of Hussein

There were some signs yesterday, including the prickly, inflamed language of a Foreign Ministry statement on the palace inspection, that the trigger for its outburst on the palace inspection might have come from Hussein.

Using the sort of confrontational imagery that he often has when challenged, the ministry asked why the inspectors had not worn protective suits for the palace visit if they really believed there might be weapons hidden there.

"Was their visit really to search for banned weapons, or for other aims?" the statement read.

It added: "Is this the beginning of the bad behavior that the United States, Britain and the Zionist entity" - meaning Israel - "want to impose on the United Nations?

"The coming days will prove whether the inspectors are clinging to their neutral international identity, or will bow to American and British pressures and blackmail and become an eye for spying on targets and for purposes not mentioned in the Security Council resolution."

There have been nearly 20 inspections since the U.N. teams started work here Nov. 27, including two yesterday at the Muthanna and Tuwaitha complexes, the main centers used in the 1980s and 1990s for Iraq's nuclear and chemical weapons programs. By singling out the palace visit from all the others, the government abandoned its earlier accommodating tone.

In effect, it joined an edgy three-way exchange, stretching from Baghdad to Washington, that began with Bush saying Monday that the results of the initial inspections were "not encouraging."

Yesterday the inspectors joined in the fray, offering what amounted to a riposte to Bush.

Demetrius Perricos, head of the team conducting the biological, chemical and missile inspection, was asked last night whether there were differences between Bush's downbeat assessment and the teams' appraisal of their progress in the first week. "You bet there are differences," he told reporters.

"The people who sent us here are the international community, the United Nations," Perricos, who is a Greek citizen, said. "We are not serving the United States, we are not serving the United Kingdom."

Information withheld

The inspections chief implied that Bush bore some responsibility for the huge challenge facing the inspection teams, saying the United States had withheld from the inspection teams some, if not most, of the intelligence information on which the United States has based its insistent allegations that Iraq is hiding secret weapons projects.

On Tuesday, Bush again accused Hussein lying, saying that although the Iraqi leader "says he doesn't" have weapons of mass destruction, "He's got 'em. He's not only got 'em, he's used 'em."

Asked about Bush's statements at the news conference in Baghdad, Perricos said: "I hope you will understand that we are not getting all the intelligence that President Bush is getting.

"We are not being served with the same intelligence that a national authority has, and the national authority in the United States has more intelligence than we have."