Updated

The chief U.N. weapons inspectors, wrapping up a critical two-day visit, urged Iraqi officials on Tuesday to look again in their nuclear, chemical and biological "stocks and stores" to ensure they have no weapons-making to report.

Iraq's position that it has no weapons of mass destruction "must be convincingly shown by documentation, by evidence," said Hans Blix, head of the U.N. weapons-hunting team.

"We don't think that has yet been convincingly done."

Blix and chief U.N. nuclear watchdog Mohamed ElBaradei spoke with reporters after Iraqi officials confirmed they would meet a U.N. deadline and file by Dec. 8 a comprehensive list of nuclear, chemical and biological programs, including any meant to develop weapons.

The two U.N. officials offered a "light at the end of the tunnel" for Iraq, however, saying that if the Baghdad government cooperates fully with their inspections, they might be able to report in about one year that it has complied with Security Council requirements and U.N. economic sanctions on Iraq should be lifted.

Blix and ElBaradei left Iraq on Wednesday for Cyprus, flying out of the capital's airport, after leading advance teams of about two dozen U.N. officials here on Monday to resume the weapons inspection program. Their departure was expected. Most of the team stayed behind Wednesday and additional inspectors arrive next Monday. The first field operations are expected by Nov. 27.

The latest Security Council resolution calls the inspections a "final opportunity" for Iraq to meet its post-Gulf War obligations to give up any weapons of mass destruction. President Bush has threatened military action if the Iraqis don't disarm.

A seven-year inspection regime in the 1990s dismantled Iraq's nuclear program before it could build a bomb, and destroyed large amounts of chemical and biological weapons and longer-range missiles forbidden by postwar U.N. resolutions.

But some chemical weapons in particular were believed never destroyed, and U.S. intelligence reports suggest the Iraqis may have rebuilt some weapons programs since the inspectors pulled out in 1998.

The new Security Council resolution gives the U.N. teams greater powers to inspect Iraqi sites anywhere at any time.

The most senior official on the Blix-ElBaradei schedule of meetings here was Foreign Minister Naji Sabri. After that session late Tuesday, ElBaradei, director general of the International Atomic Energy Agency, told reporters, "I think we heard from the Iraqi side they will do everything humanly possible to cooperate."

Blix said the Iraqis had agreed in their discussions to open a U.N. inspectors office in the northern city of Mosul, and to expand their Baghdad office to accommodate the hundreds of international weapons experts who will come and go in coming months.

The Swedish ex-diplomat, chairman of the U.N. Monitoring, Verification and Inspection Commission, reaffirmed the importance of Iraq's upcoming Dec. 8 list. It is the standard by which the international community will judge whether President Saddam Hussein's government is lying or telling the truth about its interest in the most advanced weapons.

"We have tried to impress on them that they must look into their stocks and stores and see if there's something they should declare," Blix said.

He then referred to Iraq's known production of deadly mustard gas in the 1980s. Although those weapons were believed largely destroyed by U.N. teams in the 1990s, some may remain hidden in Iraq.

"The production of mustard gas is not like the production of marmalade," Blix said. "You must keep track of what you produced."

Earlier, Iraqi presidential adviser Amir al-Saadi, asked by reporters whether Iraq would meet the Dec. 8 deadline, replied: "Yes. Within 30 days (of passage of the U.N. resolution), as the resolution says, a report from Iraq will be submitted on all the files of nuclear, chemical, biological and missile files."

But he gave no indication of the likely character of that Iraqi declaration — that is, whether it will contain anything beyond an inventory of Iraqi work in peaceful uses of nuclear, chemical and biological materials.

Al-Saadi also was asked whether Iraq would grant inspectors unfettered access.

"Yes," he said, "as stipulated in the resolution and as we have agreed with them."

The skies over Iraq were reported quiet on Tuesday. The day before, when Blix and ElBaradei arrived here to begin the historic new round of inspections, U.S. warplanes bombed Iraqi air defense systems in the northern "no-fly zone." The U.S. military said the attack was launched after Iraqi gunners fired on the jets during routine patrols.

In Washington, White House spokesman Scott McClellan said the Iraqi anti-aircraft fire "appears to be a violation" of the latest U.N. Security Council resolution.

But U.N. Secretary-General Kofi Annan took issue with that interpretation, telling reporters in Kosovo that "I don't think the Council will say that this is in contravention of the resolution that was recently passed."

The 15-member council has never specifically approved the flights over northern and southern Iraq, which Baghdad considers violations of its sovereignty. China's U.N. ambassador, Wang Yingfan, whose government wields a veto in the council, said Beijing had "a different understanding" than Washington about whether Iraq's anti-aircraft fire violated the new resolution.