Tens of thousands of angry Turks took to the streets for the funeral of 15-year-old Berkin Elvan who died on Tuesday after months in a coma.

He was shot in the head by a high-velocity gas canister fired by police during nationwide protests last June against Prime Minister Recep Tayyip Erdogan's Justice and Development Party (AKP) government as he went to buy bread.

"Berkin's murderers are the AKP police," the mourners shouted as they took the teenager's coffin from an Alevi house of worship to the cemetery.

They also chanted: "Erdogan killer," "Government, resign," "Berkin Elvan is immortal" and "Everyone against fascism."

President Abdullah Gul said on Tuesday that he was saddened by the news of Berkin's death, adding: "I extend my condolences to his family. I share their pain."

But his grieving mother Gulsum Elvan retorted: "It's not God who took my son away but Prime Minister Erdogan."

Mr Erdogan's son and close associates have been implicated in a corruption scandal, prompting the militant trade union confederation Disk to say: "Their children steal millions and our children are killed when they go to buy bread."

Spontaneous protests broke out across Turkey on Tuesday when news of the teenager's death broke.

Police used tear gas in Istanbul to disperse crowds that gathered outside the hospital where Berkin died. Water cannon and tear gas were deployed in Ankara to break up demonstrations and police arrested over 100 people in Izmir.

There were also significant mobilisations of protesters in Adana, Samsun, Eskisehir and Mersin.

Shopkeepers in working-class Istanbul district Okmeydani, where Berkin's family lives, closed their shops as a mark of respect.

Turkish voters are set to go to the polls for local elections on March 30, which Mr Erdogan has admitted will be widely seen as a referendum on his government.

Mr Erdogan and his AKP party have been on the back foot in recent months, especially since December when police arrested dozens of people close to the government on suspicion of corruption.

He has responded by sacking thousands of senior police officers and legal officers involved in investigating the charges.