An estimated 15,000 protesters marched in the main city of Diyarbakir in the majority Kurdish southeast of Turkey, but clashses erupted when some demonstrators threw stones and fireworks at anti-riot police who tried to block the march, an AFP correspondent on the scene reported.

Police used tear gas and water cannon to disperse the crowd. One protester and one police officer were wounded, according to local sources, who also said several people were arrested.

The Anatolia news agency reported that four police were injured in the clashes.

The demonstration was called by the Kurdish Democratic Society Party to support Ocalan's claims of poor treatment at the Imrali island prison, where he has been serving a life sentence since 1999.

Turkey's justice ministry published photos on Friday to show that Ocalan's jail conditions were the same as those of other inmates in high-security prisons and said they met international standards.

Ocalan, 61, was the sole inmate at the prison on Imrali island until new prisoners arrived last month, after the Council of Europe's Committee for the Prevention of Torture (CPT) criticised Ankara for violating Ocalan's human rights by keeping him in solitary confinement.

More demonstrations took place on Saturday in the southeast town of Yuksekova where a 19-year-old suffered a serious head injury from a teargas grenade during clashes with police, and one officer was also injured, according to local security sources.

The PKK, considered a terrorist organisation by Ankara and much of the international community, has a waged a bloody insurgency for Kurdish independence since 1984 which has claimed some 45,000 lives.