An Istanbul court has blocked a conference discussing the World War I massacre of Armenians, which was due to open today.
The move has embarrased Turkey and angered EU states just 10 days before the planned start of EU entry talks.
Turkey has always denied claims that Ottoman Turkish forces committed genocide against local Armenians during World War One, but under pressure from the European Union, has called for historians to debate the issue.
An Istanbul court yesterday barred two universities from hosting the conference pending information on the qualifications of the speakers.
They also wanted to know who was participating and who was paying for it. Prime Minister Tayyip Erdogan said the court verdict had "nothing to do with democracy".
However, Justice Minister Cemil Cicek later said there was nothing to stop the conference from being held at another location. A spokeswoman for Istanbul's Bilgi University said the rectors there had agreed to host the meeting.
The court's verdict has been condemned by the European Commission. "The absence of legal motivations and the (timing) of this decision a day before the conference looks like yet another provocation," Krisztina Nagy, the EU executive's spokeswoman for enlargement, said today.
The Armenian conference had already been postponed in May after the justice minister accused its organisers of treason.
The group of Turkish lawyers who appealed to the Turkish court to have the conference stopped welcomed its verdict. "The real aim of this conference ... was to push the country into chaos, break it up and create a (greater) Armenia and a Kurdistan," the group's chairman Kemal Kerincsiz told reporters.
Turkey accepts many Armenians were killed during World War I, but says they were victims of a partisan conflict which also claimed thousands of Turkish lives. Turkey denies any systematic genocide of Armenians.