The two-day summit in Russia's second city, in which French President Jacques Chirac will join Russian President Vladimir Putin and German Chancellor Gerhard Schroeder, marks a defining moment for the peace camp.

Infuriated after weeks of wrangling at the United Nations failed to secure UN approval for the US-led invasion, the US administration is highly reluctant to grant the world body any role other than humanitarian in Iraq after the fall of President Saddam Hussein.

But divisions have emerged between US President George W. Bush and his close ally British Prime Minister Tony Blair who reportedly wants the United Nations to oversee any interim Iraqi administration while Washington seeks initial US-British military control.

Some observers speculate that the anti-war trio will try to prise Blair away from the US embrace to formally lend his weight to their efforts.

"The Russian position on the UN's role in a post-war Iraq is well-known: only this organisation can legitimize any temporary administration," said the leading Russian daily, Izvestia.

"Russian diplomats believe that the coalition in the UN Security Council before the start of the war could fall apart," it added, in reference to Britain.

But in a sign of the difficulties in challenging the United States, UN Secretary General Kofi Annan Tuesday abruptly cancelled a whirlwind tour of Britain, France, Germany and Russia this week to discuss the postwar reconstruction of Iraq.

"Russia, France and Germany are obliged to repeat that the UN should participate in the administration of Iraq, but I don't see anything that will make the Americans change their plans and stop them enjoying their victory," commented Sergei Kazionov from the Institute of Global Economy and International Relations.

"Kofi Annan decided not to stick his neck out. He understood that nothing will come of it. The United Nations has neither the prestige nor any real possibility of administering Iraq," the foreign policy expert added.

Bush and Blair on Tuesday pledged at a joint press conference in Belfast that the United Nations would play a "vital role" in post-war Iraq.

However they gave no clear indication of how involved the world body would become.

US Secretary of State Colin Powell, who encouraged Bush to seek UN approval before the war, is known to favour strong UN involvement but he faces opposition from powerful hawks such as Defence Secretary Donald Rumsfeld and Vice-President Dick Cheney.

Hopes of splitting the US-British alliance are unlikely to materialise, the director of the Moscow branch of the Washington-based Carnegie Endowment think-tank, Robert Nurick, told AFP.

The best France, Germany and Russia can hope for is some form of compromise that would grant the United Nations a role in overseeing elections to a new Iraqi government or brokering a power-sharing accord as in Afghanistan, he said.

"If the meeting is viewed as an attempt by the three to enlist Britain in opposition to the US, we will have yet another public spat. All the signs that this is not a role that Tony Blair will play, whatever his views are," he said.

"But there's a big grey area, beyond the interim period -- how is the new government going to be chosen, who is going to administer elections? If it's the United Nations, which some people in the US support, then you could find some middle ground," the analyst added.

SPACE.WIRE