(BRUSSELS) - EU leaders clashed Friday over whether the bloc could keep taking in new member states without the Lisbon reform treaty, which was holed by Irish voters.

The reform charter was intended to make the enlargement process more manageable by streamlining the European Union's institutions, but the "No" vote in the June 12 Irish referendum has left the treaty in limbo.

At the 27-member bloc's summit in Brussels, EU leaders agreed to put talks on what to do about the treaty on hold until October.

Some EU leaders, led by French President Nicolas Sarkozy, warned that the union cannot absorb new members without the treaty -- which was expressly designed to cope with enlargement.

But Sarkozy's rhetoric was "unacceptable" to Polish Prime Minister Donald Tusk.

He and other EU leaders have insisted that the expansion process must continue and candidates should not be shut out while member states resolve the Irish "no" -- which could hold up reform plans for years.

Sarkozy, whose country assumes the EU's rotating, six-month presidency on July 1, warned: "Without the Lisbon Treaty, there is no enlargement.

"I would find it very strange that Europe has trouble agreeing on its institutions but that it would be able to agree to allow in a 28th, 29th or 30th member," he said.

German Chancellor Angela Merkel backed up Sarkozy.

"I agree. The Nice Treaty effectively limits the union to 27 states."

And Luxembourg Prime Minister Jean-Claude Juncker, the EU's longest-serving leader, fought his corner.

"Without a new treaty there's no enlargement," he insisted. "One of the reasons for the Lisbon Treaty was the capacity to enlarge."

But Tusk rebuked Sarkozy's comments.

"The idea that the referendum in Ireland renders the European perspective for Croatia, Serbia or Ukraine impossible is unacceptable," he snapped.

British diplomatic sources also said that London "does not believe that (limbo for) the Lisbon treaty would mean an end to further enlargement."

Croatia is waiting in the wings to join by 2010, while Macedonia is still seeking a date to start entry talks. Turkey is also officially a candidate country, though its passage is set to take far longer than Croatia's.

For his part, Croatian President Stipe Mesic stressed that his country's accession had already been approved by the EU's 27 member nations.

The EU is also looking to take in Albania, Bosnia-Hercegovina, Kosovo, Montenegro and Serbia as it expands further east.

"If something has been agreed, if the countries have agreed, then it has to be implemented. So it will not impact on Croatia," he said in Zagreb.

In their summit conclusions, at least, EU leaders remained diplomatic.

They said the remaining potential future members in the western Balkans, by meeting the criteria, should become candidates, with EU membership as the "ultimate goal," saying it was essential for regional stability.

Seven EU nations have yet to ratify the Lisbon Treaty, including the Czech Republic, where it is being held up by the courts, and President Vaclav Klaus has declared it dead.

However, Czech Foreign Minister Karel Schwarzenberg insisted that the EU should keep up the enlargement process nonetheless.

"It is necessary to go on with our talks with all the Balkan countries, it is necessary to conclude accession talks with Croatia and we will work on that very intensively," he vowed.

"We shoudn't make the Balkan states, where the reform process highly depends on the possibility of one day accessing the EU, victims of inside EU difficulties."

Austrian Foreign Minister Ursula Plassnik echoed his call, saying: "Croatia must not become a victim of the Irish referendum rejection."

Finnish President Tarja Halonen was more sanguine, saying enlargement could continue under the existing Nice Treaty, signed in 2001 when the EU numbered just 15 nations and which Lisbon was in part devised to reform.

"I think that enlargement will go, as we say, with the old process," she told reporters.

"But don't panic."

European Council

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