U.N. weapons inspectors were delayed two hours Friday while trying to enter an inspection site, requiring the team to use its hotline to contact higher Baghdad authorities for the first time since visits resumed last month.

The inspection team was allowed into the building, Iraq's Communicable Disease Control Center, but was initially unable to enter several locked rooms. Team members had to wait two hours to enter the rooms until Gen. Hossam Mohammed Amin, their Iraqi liaison, arrived and let them in.

"It is a newly declared site and there was a need for tagging of some of its equipment," Gen. Hossam Mohammed Amin, head of Iraq's National Monitoring Directorate, told reporters outside the building. "There is no problem."

Another Iraqi official, speaking on condition of anonymity, said the problem was the result of the inspections taking place on Friday, the Muslim day of prayer, when the keys for the locked rooms were not readily available.

Friday's inspections marked the first time the U.N. teams have been in the field on the Muslim day off since returning to work Nov. 27 after a four-year break.

The inspectors subsequently sealed the doors against their being opened when the U.N. teams were not present.

A team of inspectors also visited the Ibn Al-Haithem Company, which Iraqi officials would only describe as an industrial facility for the military six miles north of Baghdad.

On Thursday, Amin said the new round of U.N. weapons inspections had disproved "groundless" allegations by Western intelligence agencies that 10 Iraqi sites may be helping to produce banned weapons.

He called the intelligence reports "just a lie." The inspectors have not yet issued their findings, however, from visits to the 10 installations.

At a news conference, Amin also was asked about an unconfirmed U.S. report that an Iraqi chemical weapon was delivered to an Islamic extremist group affiliated with Al Qaeda.

"This is really a ridiculous assumption from the American administration," he said.

The general, the Iraqi government's chief liaison to the inspectors, spoke with reporters after a day in which the greatly reinforced corps of U.N. monitors — quadrupled to 100 this week — observed a test launch of a short-range Iraqi missile to verify it does not exceed U.N. range limits, and paid unannounced visits to a half-dozen other sites.

The U.N. inspections have resumed under a new U.N. Security Council resolution requiring Iraq to report on nuclear, biological, chemical and missile research and production. It filed that 12,000-page U.N. declaration last weekend.

The resolution also mandates that Iraq surrender any weapons of mass destruction, which it denies having. The U.S. government says it is sure Baghdad retains such weapons, and threatens war if Iraq fails, in Washington's view, to comply with U.N. disarmament demands.

In a round of inspections in the 1990s, after Iraq's defeat in the 1991 Gulf War, the United Nations destroyed tons of Iraqi chemical and biological weapons and dismantled Iraq's nuclear weapons program.

The U.N. monitors suspected they may not have traced all the weapons, however, and recently published British and U.S. intelligence reports said new construction at old weapons sites and other activities suggest the Iraqis may have resumed making weapons of mass destruction.

In Washington, U.S. officials said Iraq's weapons declaration does not account for a number of missing chemical and biological weapons and fails to explain purchases U.S. intelligence believes are related to Saddam Hussein's nuclear program. The officials spoke on condition of anonymity.

The tentative U.S. conclusion that the report is lacking sets the stage for a critical set of decisions by President Bush, who has threatened to disarm Iraq by force.

In their 58 site inspections since the U.N. operation resumed, the arms monitors have visited some of the sites considered suspect, including a chlorine plant whose product could be used in chemical weapons and an animal-vaccine plant linked to Iraq's previous biological weapons program.

Ten of the sites newly inspected "were allegedly said to practice and conduct some prohibited activities," Amin told reporters, without identifying the locations. "The visits of the inspection teams proved that those allegations are groundless."

The inspectors have generally not reported the results of their visits, including to the chlorine and vaccine plants. But after an inspection Wednesday at a nuclear site questioned in the intelligence reports, the nuclear monitors reported they had verified it was not involved in revived weapons work.

Amin said the Iraqis thus far are satisfied with the "professionalism" of the inspections, and he hoped the economic sanctions imposed on Iraq since it invaded Kuwait in 1990 could be lifted within eight months.

Under U.N. resolutions, if the inspectors ultimately report full Iraqi cooperation in their disarmament work, the Security Council is supposed to consider lifting those sanctions.