The worst violence erupted in the city of Van
Bloody clashes have erupted at cities in south-eastern Turkey between police and demonstrators during celebrations of the Nowruz spring festival.
More than 130 people were arrested and scores injured in the battles.
In the city of Van, police used batons, tear gas and water cannon on protesters who hurled rocks and chanted slogans in support of the PKK Kurdish rebel group.
The unrest follows last month's incursion by Turkey's army into northern Iraq to target the PKK.
Thousands of people took part in the demonstration at Van, during which barricades were set up and fires lit in the streets.
Local police chief Mehmet Salih Kesmez told AP news agency nearly 40 protesters and 15 police officers had been injured.
Four, including a police officer, were being treated in an intensive care unit, he said.
Clashes, arrests and injuries were also reported in the cities of Hakkari and Siirt.
On Friday, protesters shouted the name of jailed PKK leader Abdullah Ocalan during Nowruz celebrations in Diyarbakir, but police did not intervene.
Molotov cocktails were thrown during protests on Friday in Viransehir.
Unrest was also reported among Kurdish communities in western Turkey, including in Mersin and Izmir.
Turkey said its week-long offensive in northern Iraq last month targeted bases used by up to 3,000 Kurdish rebels as a springboard for attacks across the border.
The Turkish military said more than 200 PKK militants and about 30 members of the Turkish security forces had died.
The PKK, which wants autonomy for Kurds in south-eastern Turkey, is designated as a terrorist organisation by Turkey, the US and EU.
More than 30,000 people have been killed since the PKK began its armed campaign in 1984.