After deliberating for just over an hour, the Istanbul court found the academic guilty of helping Kurdish rebels carry out an attack 15 years ago on an Istanbul spice market popular with tourists.

Selek lives in exile in France and did not attend the trial, but she had dozens of supporters in court who had travelled from around Europe and responded with outrage to the ruling.

"Fascists! Fascists!" a group of Italian feminist activists shouted at the magistrates, while a German group yelled "Solidarity with Pinar Selek!"

Selek said from her home in Strasbourg that she planned to seek political asylum in France.

"It's very difficult but I am going to fight to the end," she told AFP.

"I'm tired but I'm strong, thanks to the solidarity of the people around me."

Selek, who is known for her research on marginalised minorities such as transsexuals and Kurds, was arrested and jailed at age 27 on charges of involvement in the explosion after she refused to give police the names of rebels she had met during her research.

She was freed in 2000 after the publication of a report blaming the explosion on a gas leak.

Turkish courts acquitted her three times of involvement, basing their decisions on the primary witness's retraction of his testimony and a lack of evidence that the blast was a bomb attack.

But the High Court of Appeal threw out the verdict each time.

Selek's lawyers condemned the holding of a fourth trial, arguing it was a procedural violation and refusing to take part after the judges overruled their objections.