Both he and a British spokesman minimized reported differences between the United States and Britain over how important a role the United Nations should play.

Speaking on Air Force One on his way with President George W. Bush to a summit with British Prime Minister Tony Blair in Northern Ireland, Powell said about setting up the interim authority: "We'll be sending people over this week to begin the process of bringing together a group that would constitute the authority."

He said the military campaign against the regime of Iraqi leader Saddam Hussein was "going exceptionally well" but warned about giving a timetable for how soon it would be over.

Britain reportedly wants the United Nations to oversee any interim Iraqi military administration, while Washington seeks initial US-British military control.

Powell said: "There isn't as much debate and disagreement about this as you might read in the newspapers."

The United States and Britain agree that the United Nations should play a role in distributing humanitarian aid and running the oil-for-food program to raise money for this.

But Powell said that when fighting ends "the military commander must be in charge for a period of time to stabilize the country."

"The coalition, having spent the treasure, having taken the political risk and having paid the cost in lives, must have a leading role as we transition from a phase of hostilities to post-hostilities to reconstruction, to putting in place a representative government that belongs to the Iraqi people," Powell said.

A spokesman for Blair said there were "practical commonsense issues that have to be sorted out" and urged journalists to wait until talks here were finished.

He said: "You can be assured that anything we will do will be within international law."

"The aim of all three voices in this, ourselves, the Americans and the UN is precisely the same - an Iraq not run by us, not by the Americans or by the UN but by the Iraqis as soon as possible," the Blair spokesman said.

He said Britain sees a significant role for the United Nations in rebuilding Iraq, saying the allies had agreed at a summit in the Azores in March on the desirability of having UN resolutions on both the oil-for-food programme and reconstruction.

He said Britain agrees that in the immediate aftermath of the conflict the coalition partners would have to run the country.

But he noted that retired US general Jay Garner, who will head the Pentagon-led post-war administration, had himself given what the spokesman described as "an indicative timescale" of around 90 days for the duration of his mission.

After that there would be a transition to an interim Iraqi authority.

The spokesman said: "That should be, we are totally agreed on this, as representative of the complex multi-ethnic nature of Iraq as possible."

"The UN should be involved in that in a way that endorses that new Iraqi authority," he said.

Finally, there would be a third transition to a properly constituted Iraqi government.

Both Powell and the British spokesman said the United Nations had made it clear that it had neither the capacity nor the desire to run Iraq.

But in New York, UN Secretary General Kofi Annan warned that UN involvement was required to confer legitimacy on any post-conflict administration in Baghdad.

SPACE.WIRE