The protest in Dogubayazit was just one of several held across Turkey by Kurds over the past three days, following allegations that Ocalan was mistreated in prison.
In Diyarbakir, the main city in Turkey’s Kurdish-dominated southeast, demonstrators burned tyres and formed barricades during a visit by Recep Tayyip Erdogan, the country’s prime minister, on Monday.
There were no immediate reports of any injuries.
Meanwhile, police in the city of Van detained dozens of people following a protest there, while in nearby Hakkari, protesters hurled stones at the local headquarters of Erdogan’s ruling party.
Ocalan’s lawyers said last week that he was removed from his cell by guards carrying out a search, was forced onto the ground when he objected and was threatened with death.
The government has denied the claims.
Mehmet Ali Sahin, Turkey’s justice minister, said: “We ordered an investigation. He has not been mistreated, he has not been subjected to any kind of negative treatment, he was not tortured.”
Ocalan is serving a life sentence on a prison island off Istanbul for leading a war for autonomy for the country’s Kurdish minority in the southeast.
The conflict has left tens of thousands of people dead since it began in 1984.