Protesters have clashed with police in cities across Turkey after the death of a 15-year-old boy, who was hit in the head by a tear-gas canister during anti-government demonstrations last summer.

Police unleashed water cannon and tear gas on thousands of demonstrators.

Berkin Elvan, then 14, got caught up in street battles in Istanbul between police and protesters on 16 June while going to buy bread for his family.

He slipped into a coma and became a rallying point for government opponents, who held regular vigils at the hospital where he lay in intensive care.

This evening, police fired water cannon and tear gas in Ankara's central Kizilay square to scatter several thousand protesters who called for the government of Prime Minister Tayyip Erdogan to resign.

The police pursued the protesters into side streets where small clashes continued.

There was similar police intervention against thousands of protesters on both the European and Asian sides of Istanbul, among dozens of places across Turkey where posts on social media had called for protests this evening.

In the Mediterranean city of Mersin, two women were injured when struck by a water cannon vehicle, one of them suffering a head wound, the Dogan news agency said.

Four police were also reported injured in the clashes there.

Police detained 20 people as they skirmished with protesters trying to march to the offices of Mr Erdogan's AK Party in the Black Sea city of Samsun, Dogan reported.

In the southern city of Adana, protesters threw stones at police lines as water cannon vehicles advanced against them, spraying water.

Large numbers also protested in the western cities of Izmir and Eskisehir in the most extensive protests since last summer's unrest.

Residents in some Istanbul districts banged pots and pans with spoons from the windows of their apartment blocks, reviving a form of protest popular during the summer.

Crowds chanted as mourners carried Berkin's coffin, wrapped in red cloth and strewn with red carnations, to a "cemevi", an Alevi place of worship, in central Istanbul.

Alevis are a religious minority in mainly Sunni Muslim Turkey who espouse a liberal version of Islam and have often been at odds with Mr Erdogan's Islamist-rooted government.

Among the throng of up to 1,000 people, some waved plain red flags, while shopkeepers in the Okmeydani district pulled down their shutters as a mark of respect.

Berkin's mother, flanked by a group of women, stood crying at an open window.

"We have come here because of the murderer police. They will be held to account. Berkin Elvan's blood will not be left on the ground," said Ahmet Ekinci, one of those in the crowd.

Elvan was the sixth person to die in violence during nationwide protests in late May and June over Mr Erdogan's plans to bulldoze an Istanbul park.

The protests turned into one of the biggest shows of public defiance of Mr Erdogan's 11-year rule.

President Abdullah Gul, the first senior figure to publicly comment on Berkin's death, sent his condolences to the family.

Ahead of elections, the prime minister is also battling a corruption scandal that has become one of the biggest challenges of his decade in power.

Istanbul and Ankara have both seen protests in recent weeks against what demonstrators regard as Mr Erdogan's authoritarian reaction to the graft affair, which has included new laws tightening internet controls and handing government greater influence over the appointment of judges and prosecutors.