Iraq stopped a team of U.N. inspectors from carrying out searches for banned weapons in Baghdad Thursday, an Iraqi official said, threatening to reignite a dispute that nearly led to war six months ago.

It was the most defiant Iraqi gesture since a crisis over weapons searches at presidential compounds was resolved in February, averting a possible U.S. and British military strike. Thursday's step came a day after President Saddam Hussein froze cooperation with inspectors to protest eight years of economic sanctions.That move followed a breakdown in talks between Iraq and the United Nations. Chief U.N. weapons inspector Richard Butler left Baghdad on Monday and was briefing the U.N. Security Council in a closed session Thursday morning.

Blocking the inspectors will likely return the issue of U.N. sanctions to international attention and could renew a confrontation with the United States. U.S. officials had downplayed Saddam's announcement Wednesday, saying they would wait to see what happened when inspectors tried to work.

The sanctions were imposed after Iraq's 1990 invasion of Kuwait and have crippled the economy by banning the free sale of oil, the country's economic mainstay. To lift them, inspectors must certify Iraq's weapons of mass destruction have been dismantled.

Officially, the U.N. team was stopped Thursday because government officials refused to accompany it, said an Iraqi official. Without escorts, U.N. teams cannot conduct their work.

In the past, the Iraqis have withheld escorts as a way of impeding the U.N. inspections, which are usually carried out as surprise visits.

The U.N. team was not allowed to conduct "discussions with Iraqi authorities on arms or visits to sites or searches for past weapons," the official told the Associated Press.

U.S. National Security Council spokesman P.J. Crowley called Iraq's decision "counterproductive," and warned "there is no prospect that Iraq will obtain a lifting of sanctions until it fully cooperates."

He confirmed that Iraq did not provide its normal "minders" for an inspection team carrying out an unscheduled check, but said normal monitoring otherwise continued.

In another step toward confrontation, Iraq told the International Atomic Energy Agency it could no longer carry out surprise inspections of Iraq's nuclear program.

"This is not acceptable and we are contacting the president of the Security Council," David Kyd, an IAEA spokesman in Vienna, Austria, said Thursday.

Iraq has sought to shift the United Nations and IAEA from inspections of potentially clandestine sites to monitoring places already searched, a proposal backed by Russia in the Security Council last month. The United States headed off the move.

As a result, the government has allowed monitoring of the inspected sites to continue. About 460 sites in Iraq have been inspected and are under monitoring. About 100 U.N. experts visit the sites or use remote-controlled cameras and sensors as part of a surveillance system set up in 1994.

"Ongoing monitoring continues," Janet Sullivan, a U.N. spokeswoman, said.

"We are strongly convinced that Iraq is not the only one to blame for this situation," Yuriy Fedotov, Russia's No. 2 man at the United Nations said after the Security Council met Wednesday.

The Russians and French, both of which have financial interests in Iraq, are trying to accelerate an end to the sanctions.

Iraq, meanwhile, called for Arab backing of its decision to suspend cooperation with U.N. inspectors.

Nabil Nagm, permanent Iraqi representative to the Arab League, said, "We are in touch with almost all of our brothers in Arab capitals. We are hoping that the Arabs would come up with a unified position soon.

"The Arab man on the street is frustrated with the anti-Arab U.S. position, but we are now talking about a unified stand, both official and popular," Nagm said.