Berkin Elvan's sister Ozge (C) reacts as his coffin approaches the Okmeydani cemevi, an Alevi place of worship, in Istanbul March 11, 2014. Police and protesters clashed in Turkey's two biggest cities on Tuesday following the death of the 15-year-old boy who suffered a head injury during anti-government demonstrations last summer. 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. 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. (Photo by Osman Orsal/Reuters)

People protect themselves behind a trash can as anti-riot olice fires water cannon to disperse thousands of people demonstrating following the death of Berkin Elvan, a teenage boy wounded in mass anti-government demonstrations last year, on March 11, 2014 near the Middle East Technical University (ODTU) in Ankara. Elvan's story – he spent 269 days in a coma – gripped the nation and became a symbol of the heavy-handed tactics used by police to reign in the biggest demonstrations against Prime Minister Recep Tayyip Erdogan since he came to power in 2003. (Photo by Adem Altan/AFP Photo)

Fireworks thrown by anti-government protesters explode behind riot policemen near central Taksim square in Istanbul March 12, 2014. Turkish police fired tear gas and water cannon to push back thousands of demonstrators close to Istanbul's central Taksim square on Wednesday during a protest triggered by the death of a teenager wounded in street clashes last summer. (Photo by Murad Sezer/Reuters)

A protester reacts during clashes with police in Kadikoy, Anatolian side of Istanbul, on March 11, 2014. Turkish riot police fired tear gas on March 11 at protesters massed outside a hospital after the death of a teenage boy wounded during anti-government protests last year and left comatose. Berkin Elvan, 15, who has been in a coma since June 2013 after being struck in the head by a gas canister during a police crackdown on protesters, died on March 11, his family announced via Twitter. (Photo by Bulent Kilic/AFP Photo)

Fireworks thrown by protesters against Turkish riot police explodes and illuminates the scene during a demonstration in Istanbul. (Photo by Erdem Sahin/EPA)

A Turkish protester stands in front of a riot police's water cannon vehicle during a demonstration in Istanbul. (Photo by Sedat Suna/EPA)

Turkish riot police fires tear gas to disperse protesters during a demonstration in Istanbul. (Photo by Erdem Sahin/EPA)

A demonstrator opens his umbrella as police uses a water cannon during clashes between protesters and riot police at Istiklal avenue in Istanbul. (Photo by Ozan Kose/AFP Photo)

A riot police stands near a burning barricade during clashes with riot police in Kadikoy, on the Anatolian side of Istanbul. (Photo by Gurcan Ozturk/AFP Photo)

A protester wearing a gas mask stands in front of an empty bus during clashes with riot police in Istanbul. (Photo by Bulent Kilic/AFP Photo)

A protester throws gas canister back to policemen during clashes with riot police in Istanbul. (Photo by Bulent Kilic/AFP Photo)

A protester holds a picture of Berkin Elvan during clashes with riot police in Istanbul. (Photo by Bulent Kilic/AFP Photo)

A protestor throws a stone at riot police lined up to hide behind shields during clashes with police in Istanbul. (Photo by Bulent Kilic/AFP Photo)

A protester wearing a gas mask stands during clashes with police in Istanbul. (Photo by Bulent Kilic/AFP Photo)

Turkish riot police use tear gas to disperse protesters during an anti government demonstration in Istanbul. (Photo by EPA/Depo Photos)

Riot policemen shield themselves as fireworks thrown by protesters explode next to the statue of a bull, during an anti-government protest in the Kadikoy district of Istanbul March 11, 2014. Protesters clashed with police in cities across Turkey on Tuesday 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, another pre-election headache for Prime Minister Tayyip Erdogan as he battles a corruption scandal that has become one of the biggest challenges of his decade in power. (Photo by Reuters/Stringer)

A young girl is pictured after she was wounded during clashes between riot-police and prostestors after the funeral of Berkin Elvan, the 15-year-old boy who died from injuries suffered during last year's anti-government protests, in Istanbul on March 12, 2014. Riot police fired tear gas and water cannon at protestors in the capital Ankara, while in Istbanbul, crowds shouting anti-government slogans lit a huge fire as they made their way to a cemetery for the burial of Berkin Elvan. (Photo by Bulent Kilic/AFP Photo)