The violence erupted overnight when riot police used tear gas, rubber bullets and water cannon to disperse thousands of anti-government protesters in two Turkish cities.
In the Kadikoy district of Istanbul a rally began peacefully with a series of concerts, but as night fell chaos broke out when police charged at protesters who wanted to march to the ruling AK Party's headquarters.
Protesters set barricades on fire in the street while police attempted to control the crowd by firing plastic bullets and tear gas.
Several demonstrators were arrested and an elderly man was taken to hospital during the clashes.
Meanwhile, demonstrators and riot police faced off for a sixth straight night in the southern city of Antakya in Hatay Province, near the border with Syria.
Police used gas canisters on the protesters, who had blocked off a street with barricades that were set on fire. They later moved in with water cannon to extinguish the flames.
There have been ongoing but relatively minor protests across Turkey since the major clashes of three to four months ago.
But anger intensified again last week after a 22-year-old man, Ahmet Atakan, died during clashes between demonstrators and the police in Antakya.
Atakan's family claim he was hit by a gas canister while police deny responsibility for the death.
The latest unrest comes six months before local elections, the start of a voting cycle which also includes a presidential election next August - in which Prime Minister Tayyip Erdogan is expected to run - and parliamentary polls in 2015.
RA/SHI