Zana's retrial is seen as a test case for human rights reforms

It means they will stay in prison until at least the next hearing on 21 April.

The defendants have been in prison for 10 years, convicted of belonging to the Kurdish paramilitary group, PKK.

The case was reopened last year, after the European Court of Human Rights ruled the original trial was unfair.

The four defendants - who deny the charges - have been boycotting the hearings, saying nothing has changed.

Their lawyer, Yusuf Alatas, said before Friday's hearing he was not optimistic about the chances of acquittal.

This is a copy of the old trial Head of Turkey's Human Rights Association Husnu Ondul

"I expect a verdict, but I am not hopeful that it will be a positive one," he told reporters.

Several European observers, including members of European Parliament, attended the hearing.

The BBC's Jonny Dymond says the judge in the trial said he wanted to hear from Ms Zana and the other defendants, who were not in court.

Ms Zana became a high-profile dissident when she was awarded the European Parliament's Sakharov Peace Prize in 1995 - a year after her conviction in Turkey.

No questions

The European Court of Human Rights ruled in 2001 that the trial of Ms Zana and her co-defendants, Orhan Dogan, Hatip Dicle and Selim Sadak, was unfair.

But their retrial started only in March 2003, after a series of democratisation packages were adopted in Turkey's parliament to bring the country into line with European Union standards.

Turkey is hoping to get a firm date to begin accession negotiations at an EU summit in December.

The retrial of the four former lawmakers has been widely denounced by human rights groups, who say nothing has changed.

"This is a copy of the old trial - there has been no difference in the proceedings," Husnu Ondul, head of Turkey's Human Rights Association, told BBC News Online.

"Judges at the state security court have basically said: 'Right, we will give them a retrial if they want one, but only a nominal one' and I doubt that they have re-examined the case properly."

He said the judges had not asked the witnesses any questions during the proceedings.

"They are giving Turkey's human rights reforms a bad name," he added.

Other observers have criticised the length of time the retrial has taken.

Ms Zana turned down the opportunity to leave prison on grounds of ill-health a few years ago.