US Secretary of State Colin Powell has described as "totally unrealistic" a French proposal for the United States to transfer power in Iraq to a provisional government as early as next month.
Powell: "We can't be expected to just step aside"
Mr Powell was speaking as he flew into Geneva for a meeting later on Saturday with his counterparts from the four other permanent members of the United Nations Security Council and the UN Secretary General, Kofi Annan.
On Friday, French Foreign Minister Dominique de Villepin suggested the establishment of a new Iraqi government in a month, a draft constitution by the end of the year and elections by next spring.
The US has put forward a resolution to create an international force in Iraq to ease pressure on its troops.
The war in Iraq may be over, but France and the US have still not made peace with each other, the BBC's Rob Watson in Washington says.
Several Security Council members - including France, Russia and Germany - are reluctant to approve any resolution that appears to give retrospective blessing to the Iraq war, which they opposed.
Russia has also called for a specific timeframe for the restoration of sovereignty and for the presence of international peacekeepers.
Britain is expected to support the US position, but comments made on the eve of the talks by Foreign Secretary Jack Straw, apparently accusing France of suffering from an anti-American neurosis, are unlikely to help the negotiations, correspondents say.
What Mr Annan and all the UN aid agencies trying to work in Iraq want is a real agreement that will establish security and allow humanitarian relief and reconstruction, says the BBC's Imogen Foulkes in Geneva.
Call for help
Earlier, President Bush called for more outside help, saying no free nation could be neutral in the fight between civilisation and chaos.
Opinion polls are showing falling popularity ratings for Mr Bush, as concern grows among Americans about the situation in Iraq.
But the US is not prepared to put its troops under UN command.
Its draft resolution on Iraq would leave Washington in charge of the military occupation but grant the UN and the US-backed Iraqi governing council a role in running elections.