Despite intensive lobbying in Paris on Friday, Mr Chirac told US President George W Bush by telephone that he still opposed a new UN resolution that would provide for the automatic use of force if Iraq fails to co-operate with UN demands.
The US and Britain have launched a joint diplomatic offensive to win the support of France, Russia and China - the three other permanent members of the UN Security Council - for the draft resolution.
Mr Chirac restated France's preference for a two-step process - one resolution on the return of UN weapons inspectors and a second one authorising force if Iraq failed to comply.
Mr Chirac told President Bush that France favoured a resolution that was "simple and firm, showing the unity and determination of the international community," according to his spokeswoman Catherine Colonna.
Mr Chirac "reiterated that France remains more than ever in favour of a two-step approach and that this is the view of the majority of the international community, given the seriousness of the decisions to be taken and their consequences," she added.
US Under Secretary of State for Political Affairs Marc Grossman held talks at the French Foreign Ministry on Friday, before heading on to the presidential palace to discuss the terms of the draft resolution further.
The BBC's James Coomarasamy in Paris says the difference between the US and the French approaches is a tactical one, and a compromise form of words is likely to be reached that would keep France on board.
Moscow mission
The US-British delegation moves to Moscow on Saturday to attempt to win over the Russians, who are also opposed to the proposed resolution. Another British official is travelling to Beijing over the weekend.
Russian Foreign Minister Igor Ivanov expressed further doubt over US policy on Iraq on Friday.
He said there was as yet "no clear proof" that Iraqi President Saddam Hussein had weapons of mass destruction.
But he added that it would be an "unforgivable error" to delay the return of UN weapons inspectors.
Chinese warning
China also reiterated its opposition to any military strike on Iraq which did not have UN authorisation.
Chinese Premier Zhu Rongji said that "if the weapons inspections do not take place, if we do not have clear proof and if we do not have the authorisation of the Security Council, we cannot launch a military attack on Iraq - otherwise, there would be incalculable consequences".
He was speaking after meeting French Prime Minister Jean-Pierre Raffarin.
The draft resolution - sponsored by the US and Britain - is believed to contain clauses that could provide the legal backing for possible military action against Baghdad.
Iraqi leader Saddam Hussein has offered to re-admit UN weapons inspectors unconditionally. But the US administration dismissed the offer as a ploy and says a new UN resolution is needed.
US stiffens resolve
US Secretary of State Colin Powell has warned that the US is prepared to go it alone if it cannot get the UN's backing.
And US Defence Secretary Donald Rumsfeld on Friday condemned Saddam Hussein as a "butcher" who "tortures people, kills them personally".
Saddam Hussein's son Uday appeared on Iraqi television to voice Baghdad's defiance of the US pressure.
He accused Washington of acting like an "arrogant cowboy" seeking to control Iraq's oil reserves.
"Do not imagine that they [Americans] will let you alone, because you are sitting on the [world's] number one oil reserve," he said.
US Congressmen in Iraq
Meanwhile, three US Congressmen have arrived in Iraq to assess the humanitarian situation after a decade of sanctions and urge Baghdad to give weapons inspectors unfettered access.
"We came over here because we do not want war," Democratic Representative Jim McDermott told reporters on his arrival in Baghdad.
"We want to see what the circumstances are for the Iraqi people and to see what the consequences of another war might be."
Mr McDermott is accompanied by his Democratic colleagues, David Bonior and Mike Thompson.
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