Updated

U.N. weapons inspectors and Iraqi officials sat down in Vienna Monday morning to find out how sincere Saddam Hussein was in his recent pledge to allow "unfettered access" to suspected sites.

Hans Blix, the Swedish-born head of the U.N. chemical- and biological-weapons inspectors, told reporters that the negotiations would build on the assumption that nothing in Iraq -- including Saddam's sprawling palace compounds -- would be off-limits to inspections.

"The purpose of the talks is that if and when inspections come about, we will not have clashes inside" over what the inspectors will do, Blix said. "We'd rather go through these things outside, in advance."

"Practical arrangements" will be discussed, Blix said, such as where in Iraq the inspectors would be based, their accommodations and security, and how suspect samples would be taken out of the country for analysis.

The negotiations are taking place at the headquarters of the International Atomic Energy Agency, which will conduct the nuclear-weapons inspections on behalf of the U.N.

Briefing journalists 2½ hours into Monday's talks, chief IAEA spokesman Mark Gwozdecky called the atmosphere "businesslike" and said the discussions were "very thorough."

"We're moving along nicely," he said. "They're all aware of the importance that there be no misunderstandings."

IAEA spokeswoman Melissa Fleming said the success of a new weapons inspection mission would hinge on Saddam's promise of full cooperation.

Nearly four years ago, inspectors hunting for evidence of nuclear, biological and chemical weaponry withdrew from Iraq on the eve of U.S.-British airstrikes amid allegations that Baghdad wasn't cooperating with the teams.

"We're certainly aware of what happened last time," Fleming said Sunday. "But we uncovered Iraq's secret nuclear program, and we dismantled it. We were successful last time. If we get unfettered access, we will be successful again."

"We're looking for Iraqi cooperation here, but these are not political talks," she added. "We are not going to be negotiating here. "We're going to be laying on the table the requirements we're going to have as inspectors."

The Bush administration, seeking to build support for an invasion of Iraq, has cast doubt on the inspectors' main requirement: that they be given freedom to examine whatever they wish, including Saddam's eight presidential palace compounds, which up to now have been off-limits.

Under a 1998 deal worked out between Iraq and U.N. Secretary-General Kofi Annan to keep the on-and-off mission going, the inspectors were shut out of the palaces, which encompass a total of about 12 square miles.

The United States has been drafting a resolution which would redesign the inspections regime and give the inspectors the power to enter Saddam's palaces and other closed facilities and block the Iraqi leader's movements in their hunt for weapons.

The weapons inspectors' closed-door talks, which will run through Tuesday, could provide the first glimpse into whether Saddam, who denies that Iraq has weapons of mass destruction, is serious about letting the inspectors go where they please.

Blix will be joined by Jacques Baute, the Frenchman who leads the IAEA's nuclear-inspections team, and a midlevel Iraqi delegation.

Both sides will discuss where the teams will be based in Iraq, how they will operate once on the ground, what types of sites they will demand access to and technical issues such as aircraft landing rights and visas, Fleming said.

Though the U.N. Security Council still must give final approval to the mission, the inspectors are gearing up for a mid-October deployment, Fleming said. Both inspection teams have been preparing to leave together from Vienna on Oct. 15, but the date could change, she said.

By the end of the 1991 Gulf War, IAEA assessments indicated Saddam was six months away from building an atomic bomb. Inspectors discovered that the oil-rich nation had imported thousands of pounds of uranium, some of which was already refined for weapons use, and had considered two types of nuclear delivery systems.

Over the next six years, inspectors seized the uranium, destroyed facilities and chemicals, dismantled over 40 missiles and confiscated thousands of documents.

Since then, the inspectors have developed new sleuthing technology, more powerful software and better analytical methods, and those should help make up for lost time, Fleming said.

"Our methods are even better," she said. "We have better equipment and we have a lot of expertise and experience from what took place in the '90s. We believe that if given unfettered access and full cooperation, we would have a very good chance of finding out the truth."

The Associated Press contributed to this report.