As weekend talks about Iraq's biological and chemical weapons programs ended, chief U.N. weapons inspectors got more documents from Iraqi officials Sunday -- though the significance of the new papers wasn't immediately known.

Chief inspectors Hans Blix and Mohamed ElBaradei met for more than four hours Saturday and two hours Sunday with Iraqi presidential adviser Amer al-Saadi. The two sides had "very detailed technical discussions," according to ElBaradei spokesman Mark Gwozdecky.

Blix said after the talks that he hopes Iraq is finally taking disarmament issues seriously.

"I hope I have seen a beginning of taking these remaining disarmament issues seriously," Blix told reporters after the two-day session ended Sunday. On Saturday he characterized the discussions as "useful" and "very substantial."

ElBaradei said the Iraqis had presented unspecified "explanations on some of the issues."

The pair plans to depart Baghdad on Monday.

A spokesman for the International Atomic Energy Agency said after the first session ended that the documents’ value wasn’t yet clear.

The success or failure of the weekend talks could help decide the next steps taken by the U.N. Security Council in the months-long standoff that has left the Middle East suspended between war and peace.

Between sessions, Blix and ElBaradei met with Iraqi Vice President Taha Yassin Ramadan, who pledged Iraq's "effective cooperation" in the U.N. arms inspections, the official Iraqi News Agency said.

Blix and ElBaradei were looking for quick Iraqi concessions on several practical matters in the disarmament effort, such as clearance to fly American U-2 reconnaissance planes in support of inspections.

On the more substantive issues, the chief inspectors were demanding documents or witnesses to clear up discrepancies in Iraq's accounting for anthrax, VX nerve gas and other weapons of mass destruction it says were produced and destroyed over a decade ago.

Neither chief inspector provided details of what the Iraqis offered. A senior U.N. official, speaking on condition of anonymity, said they had presented documents, but he declined to say how many or to specify their subject matter. No Iraqi officials spoke with reporters afterward.

The Baghdad talks will set the tone for reports Blix and ElBaradei will submit next Friday to the U.N. Security Council, whose member nations are searching for unanimity on the next step in the explosive crisis.

The council majority is against approving military action against Iraq.

New progress and a setback were reported on a procedural issue, that of private interviews, which is important to U.N. arms controllers.

ElBaradei's experts conducted an interview Saturday with a chemist without Iraqi officials present -- the fifth private interview in three days. But the U.N. inspection agency said a biologist sought for a private interview had declined.

It could not immediately be determined whether the chemist had been put forward by Iraqi officials or was invited by U.N. inspectors.

Weapons inspectors have said Iraqi scientists' refusal to be interviewed alone was a major concern and showed the country was not fully cooperating.

The U.S. and British governments contend that Iraq retains chemical, biological and nuclear weapons programs prohibited by U.N. resolutions and say they will disarm Iraq by force if necessary.

As the inspectors pressed for concessions, Iraq's foreign minister traveled to Iran in a surprise diplomatic move. There was no advance notice of Naji Sabri's visit to Tehran. Iran is a leading opponent of Saddam Hussein's regime but has nonetheless rejected military intervention without U.N. approval.

Also Sunday, Pope John Paul II ordered that a special envoy be dispatched to Iraq to emphasize his plea for peace and to encourage Iraqi authorities to cooperate with the United Nations.

Meanwhile, Egyptian President Hosni Mubarak said Sunday that other Arabs were powerless to avert a war, but that he had sent a plea to Saddam to find a way out of the crisis. His regime has come under increasing pressure from fellow Arab states to do more to spare the region war

The message to Iraq was to "find a way to settle this issue, because war is going to harm us all," Mubarak said in an interview with Egyptian television stations after talks on Iraq with the leaders of Syria and Libya at his seaside retreat at the tip of the Sinai Peninsula.

Mubarak also said U.S. Mideast envoy William Burns, a frequent visitor in times of crisis, would be coming to the region soon. He did not say when.

The Bush administration increasingly has expressed impatience with the U.N. inspections process. Washington was largely behind the resolution unanimously adopted by the Security Council last November to send the inspectors back with greater powers to search for forbidden arms.

U.S. and British diplomats also are considering options for a second U.N. resolution authorizing war against Iraq.

The Security Council banned Iraqi weapons of mass destruction and longer-range missiles after Iraq's defeat in the 1991 Gulf War, prompted by Iraq's invasion of neighboring Kuwait. U.N. inspectors in the 1990s oversaw destruction of the great bulk of chemical and biological weapons and dismantled Iraq's program to build nuclear bombs.

The U.N. experts resumed inspections last Nov. 27, after a four-year gap, to certify that Iraq has no leftover weapons and had not restarted the arms programs during the U.N. absence.

During Sunday's daily inspections, one U.N. team surveyed the grounds of an elementary school in the Baghdad district of Zafaraniyah. They were seen by journalists using a detection device to check a school yard area. Because of a holiday, no children were present. No immediate explanation was given of the purpose of the surprise inspection.

Meanwhile, coalition aircraft patrolling the no-fly zone in southern Iraq attacked an Iraqi military mobile command and control center near Al Kut, about 95 miles southeast of Baghdad, U.S. Central Command said in a statement. The facility's presence in the no-fly zone was a threat to coalition aircraft, the statement said.

For more than a decade, the U.S.-British coalition has enforced no-fly zones over the north and south in the name of keeping Iraqi forces from harassing Kurdish and Shiite Muslim populations in those regions.

The Associated Press contributed to this report.