European leaders are playing down the scale of divisions at their Brussels summit that made it impossible for them to agree on a constitution for the EU.
The Italian president was upbeat about the summit
Negotiations broke down over how voting will work when the EU expands from 15 to 25 members in May.
Poland and Spain insisted on keeping voting rights already secured, while France and Germany want a system to reflect their bigger populations.
There are fears the failure may deepen splits over the speed of integration.
The EU's plan to complete its constitution by next May now looks very hard to achieve, says the BBC's William Horsley, in Brussels.
And there are fears that continuing disagreements about the constitution could lead to a two-speed Europe, with a core group - including France and Germany - pushing ahead with integration.
But several leaders were playing down the scale of the divisions.
"There is no drama or crisis with a capital C," said French President Jacques Chirac.
UK Prime Minister Tony Blair said it had been better to abandon the talks, rather than holding deliberations throughout the night and coming up with a poor agreement.
"It is better to give it some time, for countries to have some
time to find an accord," he told reporters.
Italian Prime Minister Silvio Berlusconi, who chaired the summit in his role as head of the rotating EU presidency, said there was "total disagreement" on voting powers.
Number of commissioners
National vetoes on foreign, defence and taxation policy
Extent of European Parliament's influence on EU budget
But he said European leaders had managed to agree on the vast majority of points in the draft constitution, including an agreement on closer integration of defence.
"The question is: is the bottle half full or half empty?" Mr Berlusconi told reporters. "I'm a half full kind of guy."
But Swedish Prime Minister Goran Persson said talks on the constitution were unlikely to resume until 2005.
The problem now falls to Ireland, which takes over the EU presidency in January. Irish Prime Minister Bertie Ahern said he would give a progress report at the next summit in March.
The failure to reach an agreement could deepen a split within Europe about the speed of integration.
Mr Chirac told reporters after the summit that he wanted to see a "pioneer group" of countries that wanted to push ahead with integration.
"It would be a motor that would set an example," he said. "It will allow Europe to go faster, better."
German Chancellor Gerhard Schroeder also said a definitive failure to agree a constitution could lead to a "two-speed Europe".
A summit agreement in Nice three years ago gave Spain and Poland - one of the new members - almost as many votes each as Germany, despite them having smaller populations.
Warsaw and Madrid are determined to hold on to those voting powers.
However, Polish Prime Minister Leszek Miller said he was hopeful for agreement "in the coming weeks and months".
"We need to seek new ideas for a compromise, we must have more trust in each other," he told reporters.
During the talks on Saturday, Mr Berlusconi presented four alternative proposals to Spain and Poland in an attempt to break the deadlock, but without success.
All 25 leaders must approve the proposed constitution. However, an agreement is not needed in order for the enlargement to go ahead.
The constitution, drafted over 17 months by a special convention, introduces a "double majority" system of voting.
It means a vote is passed when it has the support of 50% of countries, representing 60% of the EU's population.
Medium-sized countries like Poland and Spain say the system favours big states - like Britain, France and Germany - and the very smallest nations.
Regardless of any agreement that might have been reached this weekend, the voting rules under the existing Nice treaty continue to apply until November 2009.