Flexing U.N. muscle, international inspectors roared up to one of Saddam Hussein's presidential palaces Tuesday and demanded and received quick entry, in an early test of new powers to hunt for weapons of mass destruction anywhere, anytime in Iraq. A key Iraqi official said, meanwhile, that the Baghdad government, in a long-awaited declaration later this week, will reaffirm its position that it no longer has such weapons.

The U.N. weapons monitors found spectacle and opulence inside the sprawling, riverside Al-Sajoud palace. But there was no word that they found anything else.

"The Iraqi side was cooperative," Gen. Hossam Mohammed Amin, the chief Iraqi liaison officer, told journalists afterward. "The inspectors were happy."

The U.N. team left the west Baghdad grounds after 1 1/2 hours and had no comment for reporters, as has been their practice. But the visit itself carried a message: that this time the inspectors have a free run of Iraq, under a Security Council mandate requiring the Baghdad government to give up any chemical, biological or nuclear weapons.

Access to Saddam's dozens of presidential sites was an explosive issue in the previous round of inspections, in the 1990s, when the Iraqis sought to bar U.N. monitors. It took personal negotiations between Saddam and U.N. Secretary-General Kofi Annan to reach an accommodation: Inspectors could visit with diplomatic escort and advance notice.

Those teams did eventually inspect eight disputed palaces, including Al-Sajoud, and found nothing.

The U.N. resolution adopted last month overrides such previous arrangements and mandates unrestricted access for the inspectors at all Iraqi sites. The security staff at Al-Sajoud clearly was aware of the new powers, taking just seven minutes of quick consultation by radio before opening the towering, ornate gates.

As usual, Saddam's whereabouts were not publicly known. He is known to move about frequently among dozens of presidential palaces across Iraq.

The dramatic, unannounced call on Al-Sajoud came on the sixth day of the inspections, which have been renewed after a four-year break.

The inspectors thus far, in more than a dozen field missions, have reported unimpeded access and Iraqi cooperation. In a speech Monday, however, President Bush  contended that so far in the inspection process, "the signs are not encouraging" that the Iraqis will "cooperate willingly and comply completely."

The Bush administration alleges Iraq retains chemical and biological weapons - missed during the 1990s inspections - and has not abandoned its nuclear weapons program.

Bush also said the Iraqi declaration on weapons, required by the United Nations  by the end of the week, "must be credible and complete."

On Tuesday, Gen. Amin told Baghdad reporters that the declaration "will include new elements, but those new elements don't mean that Iraq has weapons of mass destruction.

"Iraq is free of weapons of mass destruction."

The arrival of the inspectors' half-dozen U.N. vehicles at Al-Sajoud - accompanied by Iraqi escorts who are not told of the destination - sent gate guards scrambling and security men radioing for instructions or to alert comrades. Demetrius Perricos, U.N. team leader, consulted briefly with an Iraqi official, and the gates were opened.

Within a couple of minutes, Saddam's presidential secretary, Abed Hamoud, arrived and entered the palace grounds, which stretch alongside Baghdad's Tigris River.

As at other sites, palace security undoubtedly was aware it would be visited at some point, but there was no sign the staff knew it would be Tuesday. At the same time, a second U.N. team entered from a back gate, and inspectors were seen entering the huge main building, a modernized, Islamic-style palace in tan brick, with a frontage of several hundred yards.

Once the inspectors left, reporters were allowed inside the palace's spectacular entry hall, a soaring, three-story, eight-sided confection of carved white marble illuminated by a giant gold-and-crystal chandelier. It was a brief telling glimpse: Each of the walls was inscribed in huge gold letters with a poem praising Saddam.

"You are the glory," read one.

The inspectors of the 1990s eliminated tons of Iraqi chemical and biological weapons and the equipment to make them, dismantled Iraq's effort to build nuclear bombs, and destroyed scores of longer-range Iraqi missiles. Those inspectors suspect they didn't find all of Iraq's weapons of mass destruction.

Bush threatens to wage war on Iraq - with or without U.N. sanction - if it doesn't disarm. Other governments say that only the Security Council can authorize an attack on Iraq in a situation not involving immediate self-defense.

On Monday, among other visits, inspectors searched the Karama missile design plant in Baghdad - a revisit to a site inspected in the 1990s. The inspectors wanted to ensure that this key installation was not involved in producing missiles capable of ranges beyond the 90 miles permitted by U.N. resolutions after Iraq's defeat in the Gulf War .

The U.N. agency reported their inspectors found that equipment which had been tagged by earlier inspectors at Karama was missing. The Iraqis said some of it had been destroyed in U.S. bombing in 1998, when 18 cruise missiles struck the site, and some had been transferred to other locations.

In two previous instances last week at other sites, the inspectors traced similarly missing equipment to other locations. The equipment missing at Karama was not described by the U.N. agency.

In Vienna on Tuesday, a spokesman for the International Atomic Energy Agency said the body would begin later this month the painstaking process of analyzing the air, water and soil samples gathered by its inspectors in Iraq.

The agency, which is overseeing the hunt for Iraqi nuclear weapons, would be able to present results only by Jan. 27 at the earliest, said spokesman Mark Gwozdecky.

If Iraq is eventually found to have cooperated fully with the inspectors, U.N. resolutions call for the Security Council to consider lifting economic sanctions imposed on Iraq after it invaded Kuwait in 1990.

PHOTO CAPTION

Journalists visit the foyer of the Al-Sajoud palace, one of Saddam Hussein's presidential palaces along the Tigris River, after it was visited by U.N. weapons inspectors in Baghdad Tuesday, Dec. 3, 2002. Access to such sites was an explosive issue in the previous round of inspections in the 1990s. U.N. Security Council resolution 1441 adopted last month mandates free, unannounced access to all Iraqi sites. (AP Photo/Jerome Dela