Turkish news agencies say at least 14 people have died and scores were injured in clashes between Turkish police and Kurdish protesters.
The violence on Tuesday centered in predominantly Kurdish eastern Turkey, but there were clashes across Turkey and Europe as demonstrators demanded more action against the Islamic State group's advance on a town on the Syrian-Turkish border.
Watch: Turkey: Syrian town about to fall to jihadists
Turkey's private Dogan news agency reported 8 dead in the eastern city of Diyarbakir and the others in cities in the east as police used water cannon and tear gas to disperse protesters who burned cars and damaged businesses.
Curfews were imposed in five Turkish provinces.
There were also clashes in western cities, including Ankara and Istanbul.
In Brussels about 50 protesters smashed a door and pushed past police to enter the European Parliament.