Russia, Germany and France will urge the United States at a Security Council meeting Tuesday to preserve a key role for the chief U.N. weapons inspector, Hans Blix, in certifying the disarmament of Iraq, according to council diplomats.

The initiative is setting the stage for the first major confrontation in the 15-nation council since the United States' invasion of Iraq without the council's approval. White House and Pentagon officials want to exclude Blix from verifying Iraq's disarmament, according to U.S. officials.

Blix has been invited by the Security Council to provide an update on his readiness to return to Iraq to continue his effort to verify the destruction of Iraq's alleged chemical, biological and nuclear weapons, according to Blix's spokesman, Ewen Buchanan.

Blix said today that he is willing to return to Iraq if the council grants its blessing. But he said that he would require "independence" from the U.S. military and the same freedom he possessed during inspections he led from November until shortly before the start of the war in March, including the authority to go anywhere in the country and interview any Iraqi specialists he chooses. "I can't be on a leash," he said in an interview.

The United States, meanwhile, has stepped up the recruitment of current and former U.N. inspectors from the United States, Britain and Australia to participate in an American inspection unit that will verify any discoveries of banned weapons by U.S. military forces. U.S. forces to date have not uncovered any proscribed weapons.

The inspection unit, which is set to expand in the coming weeks, is planning to deploy hundreds of civilian and military weapons inspectors to aid in the hunt for Iraq's deadliest weapons, according to U.S. officials.

The effort has generated friction between the United States and its closest ally, Britain. The British government has discouraged civilian British specialists from joining until their role has been more clearly defined, according to diplomatic sources and former inspectors. "We need to have some element of independent verification," Britain's junior foreign minister, Mike O'Brien, said today.

The British government favors a role for Blix's inspection agency, the U.N. Monitoring, Verification and Inspection Commission (UNMOVIC), in certifying Iraq's disarmament. It is seeking to persuade the United States to overcome its "residual huffiness" over what U.S. officials see as Blix's failure to deliver a tougher assessment of Iraq's disarmament efforts, a council diplomat said.

Some Bush administration officials have privately criticized Blix, charging he played down the significance of Iraqi disarmament violations in order to forestall U.S. military action. Now that the war has ended, they don't want him to play a role.

"The White House doesn't trust Blix," an administration official said. "DOD [the Department of Defense] wants positively, absolutely nothing to do with UNMOVIC. Some in State [the State Department] feel that way, too; but others feel you have to have a U.N. imprimatur to win support for lifting sanctions."

A senior administration official said that the United States has not made a final decision on what role, if any, UNMOVIC might play in the disarmament of Iraq. But the issue was a topic of debate today in an interagency meeting of deputy administration department heads over the future of U.N. inspections.

European Security Council diplomats said that they would try to convince the administration that it is in its interest to invite the United Nations into Iraq to verify its claims. But one official said that a final agreement may have to wait for the departure of Blix, who plans to step down when his contract expires on June 30. "I don't think it will be Blix," one council member said. "I think it will be post-Blix."

Under the terms of U.N. resolutions, U.N. inspectors must verify progress in Iraq's disarmament before U.N. sanctions can be suspended or lifted. Any effort to deny Blix an opportunity to fulfill his mandate would complicate negotiations aimed at ending sanctions.

Pincus reported from Washington.

Chief U.N. weapons inspector Hans Blix said he is willing to return to Iraq but only with the authority he had previously. "I can't be on a leash," he said.