Updated

Washington said it already sees likely Iraqi violations as U.N. arms inspectors who returned Monday to Iraq after a four-year hiatus called on President Saddam Hussein's government to cooperate with their search for weapons of mass destruction in the interest of peace.

The inspectors arrived in the Iraqi capital as allied warplanes bombed Iraqi air defense systems in the northern no-fly zone after the U.S. military said the jets were fired on during routine patrols. Iraq considers such patrols a violation of its sovereignty and frequently shoots at them.

At the White House, spokesman Scott McClellan said Monday the Iraqi anti-aircraft fire "appears to be a violation" of the U.N. resolution that sent the inspectors back to Iraq.

It was unclear, however, whether other countries on the Security Council would consider incidents in the no fly zone serious enough to merit a response since those patrols were never explicitly authorized by the council. Defense Secretary Donald H. Rumsfeld, traveling in Chile, said the United States is waiting for a pattern of Iraqi misdeeds before going back to the council.

The return of the inspectors is widely seen as Saddam's last chance to avoid a devastating war with the United States. U.S. President George W. Bush has warned Saddam that failure to cooperate with the inspectors will bring on an American attack and that Washington will pursue a policy of "zero tolerance" toward Iraqi infractions.

Saddam's deputy, Izzat Ibrahim, told the official Iraqi News Agency that Iraq will work with inspectors to protect its people from America, but will fight "if war is imposed on us."

Chief U.N. inspector Hans Blix and Mohamed ElBaradei, who oversees the International Atomic Energy Agency, sat down Monday night with Gen. Hosam Amin, who acted as an Iraqi liaison for past inspectors, and Iraqi presidential adviser Amir al-Saadi in their first official meeting.

During a break, ElBaradei said the two sides had begun to discuss arrangements for the inspections and would continue Tuesday. "I think we are making progress," he said.

However, the long history of confrontation between the Iraqis and previous U.N. inspectors — especially over sensitive sites such as presidential palaces, mosques and military bases — cast doubt on how smoothly the two sides will be able to cooperate this time.

The gulf between the way the issue of Iraq's alleged weapons of mass destruction is perceived in the United States and throughout the Arab world was dramatically illustrated moments after Blix's white cargo plane — emblazoned with the black letters U.N. touched down at Saddam International Airport.

At a chaotic airport press conference, Iraqi and other Arab reporters demanded to know whether the inspectors expected friction with the United States and whether they would accept intelligence information from Washington. The inspectors said they did not expect trouble from the Americans and welcomed information from all over the world.

A front-page editorial in the ruling Baath Party newspaper Al-Thawra called the previous U.N. inspection program "an American organization to spy on Iraq," and said it hoped the new team would avoid that trap.

"The situation is tense at the moment, but there is a new opportunity and we are here to provide inspection that is credible," Blix said. "Inspection that is credible is the only thing that is in the interest of Iraq and in the interest of the world, and we will try to do so."

He said inspections could begin as early as Nov. 27. Blix then must report to the Security Council within 60 days about his progress.

"Total cooperation from Iraq is important to us," Elbaradei, an Egyptian, said. "We hope this is going to be the case." He promised that the inspections would be impartial and in-depth.

Under the new U.N. resolution, inspectors have the right to go anywhere and talk to anybody they want in order to determine whether Iraq still maintains banned weapons. In the past, weapons inspectors had to give advance notice of visits to sensitive sites including eight vast presidential palace complexes, losing the effect of surprise inspections.

The new resolution gives inspectors the explicit authority "to inspect any sites and buildings, including immediate, unimpeded, unconditional, and unrestricted access to presidential sites equal to that at all other sites." Blix told a news conference before leaving for Baghdad that even mosques are not off limits.

In the Bosnian capital Sarajevo, U.N. Secretary-General Kofi Annan also called on Iraq to ensure a smooth inspection program. "I urge President Saddam Hussein to comply fully for the sake of his people, for the sake of the region and for the sake of the world order," Annan said.

Now that the inspectors are back in Iraq, the government must file a detailed report of its banned weapons programs by Dec. 8, informing the United Nations either where the arms are located or providing convincing evidence that they no longer exist.

The inspectors must verify that Iraq is free of proscribed weapons before the Security Council will lift strict economic sanctions imposed after Saddam invaded Kuwait in 1990.

Russian Deputy Foreign Minister Yuri Fedotov was quoted Monday by Russia's Interfax news agency as saying Moscow would push for ending sanctions if Baghdad cooperated with the inspectors. Russia is a longtime ally of Iraq.

The Associated Press contributed to this report.