US Secretary of State Colin Powell said the Iraq war was going "exceptionally well" and that Washington wanted to move quickly on an interim authority for Iraq and would be sending a team to the region this week to begin the process.

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

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

Speaking on Air Force One on his way to the summit, 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.

"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.

The war summit, the third in two weeks for the two leaders, came as the post-Saddam-Hussein era seemed nearer since forces loyal to the Iraqi leader appeared to be crumbling in the face of US advances in Baghdad and British successes in Iraq's second city Basra.

The summit will also touch on the Middle Eastern peace process, on which the United States and Europe have differences in the timing of a "road map" for steps to take, and the Northern Ireland peace process, with Bush's arrival expected to give Blair a boost in getting peace moves re-started.

More than 1,000 anti-war demonstrators protested at Hillsborough Castle near Belfast where the talks are to be held.

Security was tight for the summit hastily announced last week, with police in Belfast responding Monday to three bomb alerts -- including one at the airport where Air Force One landed.

The Blair spokesman 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 program 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 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 no 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