Some 150 people threw stones and blocks of ice at police, who dispersed them with teargas, the sources said. Ten arrests were made.

Ocalan, leader of the outlawed Kurdistan Workers' Party (PKK), was captured in Kenya on February 15, 1999 after he was forced to leave the Greek embassy where he had been taking refuge.

The 57-year-old rebel leader was condemned to death in 1999 for the armed separatist campaign the PKK has waged since 1984 in southeastern Turkey.

The sentence was commuted to life imprisonment in 2002 after Ankara abolished capital punishment as part of efforts to align with the norms of the European Union.

Ocalan has since been kept in solitary confinement on an island in northwestern Turkey.

Kurdish activists have long been calling for an end to Ocalan's isolation and his transfer to an ordinary jail, but their appeals have so far fallen on deaf ears in Ankara.

Some 37,000 people have been killed since 1984 when the rebels first took up arms for self-rule in mainly Kurdish southeast Turkey.