U.N. weapons teams dropped in on Saddam Hussein Tuesday, paying a visit to a presidential palace in the heart of Baghdad and spending four hours searching the premises.

It was the second unannounced inspection of one of Saddam's domiciles since the monitors returned to Iraq in November. Unlike the first visit, when the U.N. personnel encountered the Iraqi president's private secretary, there was no indication that Saddam was home Tuesday.

Reporters, kept outside the gates of the Old Palace by Iraqi security officers, peeked through the gates but could see only a long road lined by palm trees on which U.N. and Iraqi vehicles were parked.

They could not glimpse the palace, which despite its name was only built after King Faisal II's assassination in 1958. Situated in the al-Karadah district along the banks of the Tigris, the Old Palace was bombed twice during the Persian Gulf War in 1991 and has since been repaired.

The U.N. weapons teams finally left without comment, but a palace official told the journalists that the inspectors had searched residential buildings and the offices of a war veterans agency.

Chief U.N. inspector Hans Blix said Tuesday that the inspectors would need months to finish their search for Iraq's nuclear, biological and chemical weapons, long-range missiles, and the programs that produced them.

However, President Bush indicated the inspectors did not have that much time.

"Time is running out for him," Bush said of Saddam. Bush told White House reporters Tuesday he had not seen any evidence the Iraqi president was disarming after more than 10 years of U.N. Security Council resolutions.

"He must disarm," Bush said. "I'm sick and tired of games and deceptions. And that's my view of timetables."

Since inspections resumed in November, they are not known to have discovered any evidence to support U.S. allegations that Saddam has hidden caches of weapons of mass destruction. But the Iraqi declaration on armaments, filed to the Security Council last month, failed to account for all the weapons material produced in the past, according to Blix.

Blix — who heads to Baghdad on Sunday with Mohamed ElBaradei, the chief of the U.N. nuclear agency — said Tuesday: "There are a great many open questions as to their possession of weapons of mass destruction" and "we need to have more evidence supplied to us."

ElBaradei said the two men "intend to impress on Iraq the need to switch from passive cooperation to active cooperation."

Elbaradei also said his agency had received from other countries "actionable information" about sites that weapons inspectors should look into.

The United States, which is deploying about 100,000 troops to the Persian Gulf in preparation for a possible invasion of Iraq, said Tuesday it was calling up Iraqi exiles who wish to assist in such an attack.

The first batch of Iraqi dissidents who have volunteered to serve with U.S. forces have been told by the Pentagon to assemble at marshaling centers in the next several days, U.S. officials said, speaking on condition of anonymity.

Up to 3,000 Iraqis are expected to be trained to act as translators, guides, military police and liaisons between U.S. forces and the Iraqi population. Washington has ruled out early suggestions that the dissidents would be used in combat.

U.N. Secretary-General Kofi Annan said Tuesday he saw no reason for an invasion of Iraq as U.N. weapons inspectors were "just getting up to full speed."

On the Arab diplomatic front, Syrian President Bashar Assad on Wednesday canceled a visit to Iran, scheduled to begin later in the day, during which he was expected to discuss efforts to avert a war with Iranian President Mohammad Khatami. Neither government gave an immediate explanation.

Despite being longtime foes of Saddam Hussein, both Syria and Iran have had less frosty relations with Baghdad in recent years and have spoken out against Western intervention in Iraq. Syria buys Iraqi oil, and Iranian pilgrims visit the numerous Shiite shrines in southern Iraq.

Iran's foreign minister on Wednesday clarified his government's position.

"Iran's stand is crystal clear. We are neither supporting the United States nor Iraq," Foreign Minister Kamal Kharrazi told the Tehran parliament, according to Reuters. "We are impartial but not indifferent."

In Cairo, Egyptian President Hosni Mubarak was quoted by state-controlled media as saying he would meet a personal envoy from Saddam on Saturday. The semiofficial state news agency has identified him as Gen. Ali Hassan al-Majid, Saddam's cousin.

Al-Majid is close to Saddam and has been linked to some of the most brutal events of his regime, including chemical attacks on Iraqi Kurds in northern Iraq in 1988, in which thousands of people were killed.

Also Wednesday, Russian Deputy Foreign Minister Alexander Saltanov headed to Baghdad for talks on the crisis, as well as on Iraq's decision to cancel a multibillion-dollar oil contract with a Russian company.

U.N. inspectors last visited a presidential palace, the al-Sajoud in Baghdad, on Dec. 3. The Iraqis did not block the visit, but complained that it was unnecessary.

Iraq strongly resisted searches of presidential grounds under a different U.N. inspection regime during the 1990s, leading to an agreement whereby such visits could take place only with notice and an escort of foreign diplomats.

However, a U.N. Security Council resolution passed in November explicitly gives the inspectors the right to visit any site in Iraqi at any time and without warning.

The Associated Press contributed to this report.