"The report issued today by the Istanbul coroner's office has determined that claims of (Ocalan) being poisoned are totally groundless," said a statement from the prosecutor's office in the northwestern city of Bursa.

The Bursa prosecutor's office oversees the prison island of Imrali in the Marmara Sea, where Ocalan has been kept in solitary confinement since 1999.

The report was based on tests done by a team of three experts, the statement carried by the Anatolia news agency said.

Ocalan's lawyers said in a written statement that they would legally challenge the report because the experts ignored their demands to also test the paint on the walls of Ocalan's cell and his cutlery for signs of poison.

Raising questions over the technical capacity of the Istanbul coroner's office, they also called for independent experts to run the tests.

"Samples from Ocalan and his cell need to be exmined by a team of independent experts in a laboratory of sufficient technical capacity," the statement, faxed to AFP, said.

Turkey had ordered the exams after Ocalan's lawyers told a press conference in Rome earlier this month that their client was being poisoned, citing tests results indicating the presence of what they described as toxic metals, including high levels of chromium and strontium.

They had said that Ocalan, 58, was experiencing breathing and skin problems, as well as pains severe enough to interrupt his sleep.

Ocalan is the head of the Kurdistan Workers' Party (PKK), which has waged a bloody campaign since 1984 for self-rule in southeast Turkey in a conflict that has claimed more than 37,000 lives.

Considered by many as the country's public enemy number one, he has been kept under tight security on Imrali since he was convicted of treason in 1999.

The PKK is listed as a terrorist organization by Turkey, the European Union and the United States, but many among Turkey's large Kurdish minority consider its members freedom fighters.