Britain has warned its European allies that if they do not collaborate over Iraq's post-war future they risk seeing the United Nations sidelined for a second time.
Straw says the UK and US could go it alone
Speaking ahead of a European Union summit, the UK's foreign secretary said the UN would have the vital role it had been promised in Iraq but only if key members of the Security Council were prepared to co-operate.
Correspondents say Jack Straw's warning was clearly intended to increase pressure on countries such as France and Germany, who opposed the war and have seats on the Security Council.
However arguments are thought to be inevitable over key issues like Iraq's outstanding debts and the validity of oil contracts struck by Saddam Hussein's regime with Paris and Berlin.
France and Germany are also believed to be anxious not to sign up to anything that might legitimise the war, which was carried out by the US and the UK without the explicit backing of the Security Council.
The EU summit in Athens is also being attended by the UN Secretary-General, Kofi Annan, who will be consulting key members of the UN Security Council on their views on a future role for the UN in Iraq.
The deep rifts that emerged among Council members in the run-up to the war have not been overcome, the BBC's Greg Barrow at the UN says.
And, our correspondent says, Mr Annan knows that if he fails to find some areas of agreement between the 15 Council members, the UN could find itself increasingly marginalised.
Mr Straw warned that if the Security Council failed to co-operate, the US and Britain would be forced to make other arrangements to clarify Iraq's post-war status.
Blair and Schroeder have been trying to heal the rift
It is the first time Britain has signalled it might be prepared to sideline the UN a second time, correspondents say.
His comments followed a meeting between UK Prime Minister Tony Blair and German Chancellor Gerhard Schroeder, who has been a staunch opponent of the US-led war.
After talks in Hanover on Tuesday, both leaders said they were agreed on the need for the UN to be involved in Iraq.
However, differences remain over the exact role to be played by the UN in Iraq, correspondents say.
Call for dialogue
Germany and France have both been clear that they expect the UN to play a central role, covering humanitarian assistance as well as offering some form of political input.
But Washington believes it should decide largely how any post-war administration is shaped, and has already began talks with Iraqi representatives.
The BBC's European Affairs correspondent, William Horsley says that while anti-war countries such as France, Germany and Russia are finding more common ground with the US and UK, progress is likely to be slow.
Greece, which holds the rotating EU presidency, has urged European leaders to find some ground for unity.
"We must do everything... to reinforce the transatlantic dialogue and avoid any worsening of relations between Europe and the United States," Prime Minister Costas Simitis said on Tuesday.