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United Nations weapons inspectors knocked on the doors of one of Saddam Hussein's presidential compounds Tuesday morning, quickly gaining entry in a test of the inspection teams' newfound power to go anywhere in Iraq.

The monitors found a spectacular, opulent palace inside the huge Al-Sajoud complex that sprawls along the Tigris River. But there was no word that they found anything else.

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

In New York, U.N. Secretary-General Kofi Annan described Iraq's cooperation — not only at the palace but in other inspections so far — as good but cautioned "this is only the beginning."

President Bush said Monday that early signs from Baghdad were "not encouraging."

Meanwhile, another Iraqi spokesman said that Baghdad will announce that it has no biological, chemical or nuclear weapons in its official declaration, due by Dec. 8.

In Vienna, Austria, Melissa Fleming, spokeswoman for the International Atomic Energy Agency, which conducts nuclear inspections on behalf of the U.N., said the Iraqis were expected to submit their report to the U.N. office in Baghdad on Saturday — one day before the deadline mandated by the Security Council.

The inspection team left the Al-Sajoud palace in western Baghdad after about 1½ hours and had no comment for reporters, as has been their practice. But the visit itself carried a significant message: that the inspectors now have a free run of Iraq, under the latest tough, U.S.-engineered Security Council mandate.

A day earlier, the United Nations announced inspectors could not find some equipment they were looking for at a missile-related site; it was not the first time in a week of inspections that such a problem arose.

Chief U.N. weapons inspector Hans Blix, speaking to the Associated Press on Tuesday at U.N. headquarters, said Iraq has not obstructed U.N. weapons inspectors during their first week of work but must explain the missing equipment.

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.

Meanwhile Tuesday, the Kuwaiti Interior Ministry said an Iraqi boat fired on two Kuwaiti coast guard vessels in northern Kuwaiti waters. The Kuwaiti vessels fired back. No injuries in the firing were reported.

Iraq, which did not comment on the firing, and Kuwait have not had relations since the 1991 Gulf War, in which a U.S.-led coalition liberated the oil-rich Kuwait from a seven-month Iraqi occupation. Few clashes along the Kuwaiti-Iraqi land and naval borders have been reported in recent years.

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 that were 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, the 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.

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.

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.

In Vienna on Tuesday, a spokesman for the International Atomic Energy Agency said the body would later this month begin analyzing samples gathered by its inspectors in Iraq. The agency, which is overseeing the hunt for Iraqi nuclear weapons, did not expect to present results before Jan. 27 at the earliest.

In a related development, an inspection team official said on condition of anonymity Monday that Iraqi had admitted it had tried, unsuccessfully, to import aluminum tubes that the United States had said might help Iraq build a nuclear bomb.

The inspection team official refused to elaborate. Iraq denies it still has nuclear weapons ambitions.

The Associated Press contributed to this report.