Even as the 25-member Union's leaders celebrate after clinching an overnight deal on negotiations with the predominantly Muslim state, surveys show most people in the European Union oppose the expansion.

British Foreign Secretary Jack Straw, exhausted after a 30-hour diplomatic marathon fraught with objections, notably from Austria, said the agreement was nothing short of historic.

"We are all winners: Europe ... Turkey and the international community," he told an early-hours news conference in Luxembourg, where he was joined by his Turkish counterpart Abdullah Gul.

Gul hailed the accord: "What is important for us is that the prospect of full membership is very clear. There is no alternative such as a privileged partnership."

The talks had been blocked by Austrian demands that the EU offer Turkey something less than full membership as part of the so-called negotiating framework, which sets out their principles and logistics.

The breakthrough came after Straw warned that failure would prove "catastrophic" for the bloc, still in turmoil following French and Dutch rejections of its first constitution in May and June.

Listen and learn

EU leaders have said those polls showed they need to listen more to the public. Yet the most recent survey by the Union's own Eurobarometer institute shows that 52 percent of people oppose Turkey's candidacy.

"Europe must learn more about Turkey," said European Commission chief Jose Manuel Barroso hours after the ceremony took place. "And Turkey must win the hearts and minds of European citizens. They are the ones who at the end of the day will decide about Turkey's membership," he said.

Britain's Tony Blair hailed the talks -- and said there was plenty of time to overcome all the "understandable" concerns.

"It's a very, very big change for the European Union, there's no doubt about that. It (would) be unnatural if there weren't worries and concerns," he said in London.

Croatia talks

In a double breakthrough, the EU also trumpeted the start of delayed talks with ex-Yugoslav state Croatia, after Zagreb was deemed by UN prosecutors to be helping find a key warcrimes suspect.

Zagreb's failure to arrest former general Ante Gotovina had previously blocked the former Yugoslav republic's bid to begin accession talks, which were originally due to start seven months ago.

In a report to the European Union on Monday, the UN war crimes tribunal's chief prosecutor Carla Del Ponte said Croatia had "fully cooperated" with The Hague-based tribunal in efforts to locate war crimes suspect Gotovina and dismantle his support network.

No guarantees

The EU insists that starting membership negotiations, which are likely to take at least a decade, do not guarantee that Turkey will actually join. Turkish Prime Minister Recep Tayyip Erdogan acknowledged the road would be long.

"The real work has just begun," he said in parliament. "The implementation (of reforms) in particular will try us and there will be a great struggle to fully implement the harmonization

laws -- we will pursue our path with the same determination."

The Organization of the Islamic Conference (OIC) hailed the opening of talks as a way to push forward dialogue between civilizations.

"This step has created a feeling of confidence and courage among nations of the Islamic world ... to pursue the democratic process ... in order to consolidate regional and international peace," OIC chief Ekmeleddin Ihsanoglu said.

But former French president Valery Giscard d'Estaing -- architect of the bloc's near-dead constitution -- immediately slammed the deal, which he has warned could lead to the end of the EU.

"France used to have a grand project: the political union of Europe," he said. "We have allowed two further enlargements which are obviously going to transform Europe into a large free trade zone: that's what I regret."