The Bush administration and Britain, its closest ally in the war against Iraq, may be headed for a collision over Iraq's interim leadership and the role of the United Nations after the ouster of President Saddam Hussein.

Prime Minister Tony Blair, seeking to broaden international influence over Iraq amid widespread fears that the Americans will exert unbridled control, believes the United Nations should lead a gathering of Iraqis to select interim leaders and shape the country's postwar administration.

Blair, who has begun seeking support in Europe for broader UN engagement, sees it as a way to add legitimacy to the remaking of Iraq and prove the value of the world body, which was damaged by the bitter fight over the war. He said Iraq "should be run for the first time in decades by the Iraqi people."

Senior UN officials consider the British idea a useful bridge and a modest way to begin developing a meaningful role in Iraq beyond humanitarian relief. But as one U.N. staff member put it yesterday, "Even on that, the Americans have more or less signaled to us, 'Forget about it.' "

Secretary of State Colin L. Powell will focus on the debate over postwar Iraq today with European counterparts who want to prevent the United States from dominating the politics and economics of a changed Iraq. He said he would seek further opinions in coming days and that no decisions would be made today.

"I think there is a consensus that says the United Nations has a role to play,"

Powell told reporters traveling with him on his brief European trip. "What we have to work out is exactly the nature of that role and how the U.N. role will be used to provide some level of endorsement for our actions, the actions of the coalition in Iraq."

"No one's earning great points in Washington by saying we have to work closely with the UN," said one US official involved in postwar planning.

After meeting with President Bush yesterday, Australian Foreign Minister Alexander Downer told reporters that he believes the US administration would support the establishment of a special UN representative in Iraq to coordinate UN activities. But the extent of the proposed envoy's responsibilities remained unclear.

The State Department favours a central role for the United Nations and other international partners in Iraq after a period of US military occupation. Opponents, doubtful about the UN's abilities and wary of constraints on US action, are prominent in the Defence Department and White House.

In debating UN tasks, officials make a distinction between relief and reconstruction. Indeed, the administration is eager for help from aid agencies that have permanent mandates to help refugees and vulnerable children, for example. US officials worked closely and quietly with the UN World Food Program to take over Iraq's essential nationwide food distribution system.

Leaders of prominent US-based aid organisations have appealed to Bush to turn the humanitarian operation over to a UN coordinator. They contend a U.N.

umbrella would shelter governments and independent organisations that want to help, but will not report to US military authorities.

"To have the UN in charge would not only use its expertise to the fullest, but it would allow a broader multilateral coalition," said Kenneth Bacon, president of Refugees International. "There are a number of European agencies that will find it very difficult to work on relief if they think it's being directed by the United States."

UN executives, in fact, do not want full control over Iraq after Hussein falls. They agree with officials in the State Department and DefenCe Department alike that such a mission is beyond the organisation's capabilities, whether measured by staffing, funding, administrative efficiency or the political unity that would be required.

"We're not looking for this role. We have a job to do on the humanitarian front. That's where our energies are focused," said UN Undersecretary General Shashi Tharoor. "There is no doubt that we are better equipped and more experienced for some tasks than others."

Asked, after recent meetings with US officials, what the Americans want to control, one UN staffer said, "As of now, everything."

Until now, important players in the Bush administration have envisioned making their own selections to an interim administration that would gradually take control of the country from US military commanders. The makeup of the authority remains a matter of debate.