U.N. inspectors drove into the desert Wednesday to the former center of Iraq's programs for weapons of mass destruction, making a return visit to check that arms building had not resumed. Earlier U.N. inspectors in the 1990s had demolished the al-Muthanna State Establishment, located in wastelands 40 miles northwest of Baghdad, after finding it had been key to Iraq's production of some of the deadliest chemical weapons known: mustard gas, tabun, sarin and VX nerve agent.

Al-Muthanna also was instrumental in the development of biological agents, apparently including anthrax.

The desert center operated under the name of the Iraqi State Establishment for Pesticide Production, but the Iraqis finally admitted to the UN monitors that al-Muthanna produced 4,000 tons of chemical warfare agent per year.

Wednesday's search came at the end of the first week of renewed inspections under a U.N. Security Council mandate for Iraq to shut down any continuing chemical, biological or nuclear weapons programs.

The inspectors arrived at the remote front gate of al-Muthanna at 10:25 a.m. after a circuitous drive from Baghdad. They were admitted quickly to what appeared to be a vast installation covering at least several square miles. From the outer gate, through a morning fog, the ruins of scattered buildings could be seen.

The site was bombed by U.S. planes in the 1991 Gulf War and then had its equipment and material destroyed under the supervision of U.N. inspectors in the late 1990s.

The clearing of al-Muthanna was a major achievement of the U.N. disarmament effort. A recent Iraqi report said the U.N. teams at al-Muthanna had destroyed 38,500 artillery shells and other chemical-filled weapons, almost 520,000 gallons of liquids, 150 pieces of equipment used to make chemical weapons, and four production facilities.

So far, the inspectors have reported the Iraqis to be generally co-operating. In New York on Tuesday, U.N.
Secretary-General Kofi Annan described Iraq's co-operation as good, but he cautioned "this is only the beginning."

Annan's assessment appeared at odds with that of President Bush , who said Monday that early signs from Baghdad "are not encouraging."

A senior Iraqi official said Tuesday that his government will reaffirm that it no longer has mass destruction weapons in a long-awaited declaration later this week.

In Vienna, Melissa Fleming, spokeswoman for the U.N. nuclear control agency, 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.

Gen. Hossam Mohammed Amin, the chief Iraqi liaison officer, told reporters in Baghdad that the Iraqi 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," Amin said.

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 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.

The Iraqi Foreign Ministry criticized the inspectors on Wednesday for their visit to the presidential palace, Al-Sajoud, the previous day.

A statement issued by an unidentified ministry spokesman questioned the validity of the visit.

"What did they search for in Al-Sajoud Palace?" the statement asked. "Was this visit really to search for banned weapons or for other aims?"

Tuesday's search of the opulent palace in western Baghdad was the first time the U.N. inspectors had entered a presidential compound since inspections resumed last week.

Inspections of presidential palaces in the 1990s had to be undertaken according to strict rules agreed with the Iraqis.

However, Tuesday's visit took place under the new U.N. Security Council mandate that gives inspectors the right to enter presidential compounds without notice or any other restriction. The visit was seen as a test of the new mandate.

The inspectors left Al-Sajoud palace after 1 1/2 hours, issuing no comment to reporters as they departed.

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. However, the inspectors reported that they suspected they had not found all of Iraq's weapons of mass destruction.

PHOTO CAPTION

An UNMOVIC vehicle blocks the entrance of the Al-Muthanna state establishment 70 kms (40 miles) north west of Baghdad after U.N. weapons inspectors entered the complex Wednesday Dec. 4, 2002. the Al-Muthanna complex was the main production facility for chemical and biological agent production in the 1990's. Previous weapon inspection teams rendered the facility inoperative. (AP Photo/Jerome Delay)