The BBC's Selin Girit witnesses Tuesday night's clashes in Istanbul
The funeral is to take place in the Turkish capital Istanbul of a teenaged boy who died died nine months after being injured during anti-government protests.
Berkin Elvan's death on Tuesday led to protests in cities across the country.
President Abdullah Gul has appealed for calm ahead of his funeral.
Berkin was injured while walking to buy bread in Istanbul in June. He was hit on the head by a tear gas canister at the height of the unrest.
Correspondents say that his 269 days in a coma gripped the country and became a symbol of the heavy-handed tactics used by police to rein in the biggest demonstrations against Prime Minister Recep Tayyip Erdogan.
News of the boy's death - the eighth linked to last year's mass anti-government protests - triggered protests across the country. In Ankara, police fired tear gas and water cannon to disperse some 2,000 protesters who chanted: "Government of Erdogan, government of corruption, resign, resign."
Police pursued the protesters into side streets where small clashes continued.
There was similar police action against thousands of protesters on both the European and Asian sides of Istanbul and in the cities of Mersin and Adana.'Fabricated'
The June protests started as a small environmental gathering to save an Istanbul park, but they quickly snowballed into a nationwide movement against the government of Mr Erdogan, which critics say has become increasingly authoritarian and corrupt.
The sons of three cabinet ministers have been arrested and accused of corruption, while Mr Erogan himself has angrily condemned as fabricated an audio recording that appears to show him talking to his son about hiding large sums of money.
He said last month that the recording, allegedly tapped and then posted on social media, was a "treacherous attack".
It appears to reveal Mr Erdogan asking his son Bilal to dispose of millions of euros in cash from a house.
The prime minister says that the corruption allegations are part of a plot to unseat him by US-based Islamic cleric Fethullah Gulen, a former ally whose is thought to have millions of followers in Turkey.
President Gul sent a message of condolence to Elvan's family in which he said that Turkey was going through difficult days and that the "mind of the state has become overwhelmed by anger and hatred".
"This atmosphere of hatred is undermining society's need for love and peace and efforts to understand one another," he said. "Little 15-year old Berkin Elvan is the latest victim of this atmosphere."
After Berkin's death was announced, his mother appeared outside Okmeydani hospital and was quickly surrounded by mourners. Tributes appeared on social media and hundreds of people gathered to show their anger.
Riot police soon arrived at the scene and protesters attacked one of their vehicles.
BBC Turkish correspondent Rengin Arslan said many in the crowd believed the police had not turned up at the hospital to ensure the safety of mourners but to make things worse.
Further protests were reported in the coastal cities of Antalya and Izmir and in the capital, Ankara, where students boycotted classes and staged sit-ins.