The death of this Turkish boy injured in protests last year has sparked fresh unrest

Police and protesters clashed in Turkey's two biggest cities on Tuesday following the death of a 15-year-old boy who suffered a head injury during anti-government demonstrations last summer.

Berkin Elvan, then aged 14, got caught up in street battles in Istanbul between police and protesters on June 16 after going out to buy bread for his family. He was struck in the head by a tear-gas canister and went into a coma.

Police fired tear gas and water cannon in the capital Ankara to disperse more than 2,000 people, mainly students from the Middle East Technical University (ODTU), who blocked a main highway to protest against the teenager's death.

Police also used tear gas in Istanbul after a crowd outside the hospital where Elvan died began pelting a police minibus with objects.

Up to 1,000 people gathered outside a 'cemevi,' an Alevi place of worship, where Elvan's body was to be taken after an autopsy. Alevis are a religious minority in mainly Sunni Muslim Turkey who espouse a liberal version of Islam and have often been at odds with Prime Minister Tayyip Erdogan's Islamist-rooted government.

The crowd outside the cemevi chanted: "Murderer state," "Berkin is everywhere, resistance is everywhere" and "Shoulder to shoulder against fascism."

"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 among the crowd.

"If you kill a 15-year old youth, a sapling, you will be held to account," he said.

Rallying point

Local media said there were also protests in the Aegean city of Izmir, where school children and university students also staged sit-ins.

Istanbul and Ankara have both seen protests in recent weeks against what demonstrators see as authoritarian measures by Prime Minister Tayyip Erdogan's government, including tightening government control of the Internet and courts, as it battles a corruption scandal.

There were calls on social media for further protests ahead of municipal elections on March 30, although the unrest has so far been nowhere near the scale of last summer.

Elvan had become a rallying point for critics of Erdogan's government and they held regular vigils at the hospital where he lay in intensive care. No police officer has been prosecuted in connection with the Elvan case.

"To our people: We lost Berkin Elvan today at 7 a.m. Condolences to us all," his family said in a message on Twitter.

Elvan was the sixth person to die in violence surrounding nationwide protests in late May and June over Erdogan's plans to tear down a park in central Istanbul. Those protests quickly turned into Turkey's biggest anti-government demonstration in years amid unhappiness with Erdogan's 11-year rule.

President Abdullah Gul, the first senior politician to comment on Elvan's death, sent his condolences to his family.

"I was saddened to hear of Berkin Elvan's death. When it comes down to it, he was just a boy," Gul told reporters.

(Additional reporting by Mert Ozkan, Umit Bektas and Humeyra Pamuk in Ankara; Writing by Nick Tattersall; Editing by Gareth Jones)