Story highlights Thousands march, mourning 15-year-old who died after nine months in coma

Berkin Elvan suffered a head wound after leaving his home to buy bread

He died Tuesday; mourners blame a police tear gas canister for his wound

The death caused rage against the Turkish government that sparked protests nationwide

Turkish riot police fired tear gas and water cannons to disperse thousands of mourners who attended a funeral march Wednesday for a 15-year old boy.

Throughout the afternoon, a virtual river of humanity coursed through the streets of Istanbul escorting the coffin of Berkin Elvan.

Mourners carrying portraits of the boy and red carnations chanted "Berkin Elvan, a sapling just 15 years old."

"The boy was innocent. The boy wasn't doing anything. He went to get bread and the police took a shot at him and basically killed him," said Dursun Ince, a retired engineer who was one of tens of thousands of demonstrators who participated in the march.

Berkin Elvan's death unleashed a wave of grief and rage against the Turkish government that sparked protests in cities across the country. Public messages of condolence issued by Turkey's family affairs minister, as well as a sympathetic phone call from the Turkish President to the father of the boy, did little to calm the outrage.

Elvan's mother, Gulsum, has placed blame for the critical injury her son suffered last June squarely on the government and police.

The boy was 14 years old when he was last seen conscious stepping out of his home to buy bread for his family's breakfast. His family says he was next seen 15 minutes later suffering from a horrendous head wound believed to have been inflicted by a tear gas canister fired by Turkish police. For the next nine months, the teenager lay in a coma, wasting away to a weight of just 16 kilograms (35 pounds).

Elvan was pronounced dead early Tuesday morning.

JUST WATCHED CNN crew caught in police tear gas Replay More Videos ... MUST WATCH CNN crew caught in police tear gas 03:26

JUST WATCHED Turkey wiretap war escalates Replay More Videos ... MUST WATCH Turkey wiretap war escalates 02:37

JUST WATCHED Calls for Turkish PM to flee or resign Replay More Videos ... MUST WATCH Calls for Turkish PM to flee or resign 02:49

That night, demonstrators hurled stones, bottles and abuse at Turkish riot police in several Istanbul neighborhoods.

"Killers!" angry crowds screamed at helmeted police officers on Istanbul's Istiklal Caddesi.

"You killed Berkin Elvan!" a woman yelled.

After initially holding back, squads of riot police began pursuing demonstrators through the streets. Armored personnel carriers patrolled main boulevards, hosing rioting youths with water cannons, which were also periodically used to extinguish burning barricades.

On Wednesday, a major labor union called for a nationwide strike in honor of the dead boy.

Several of the main opposition political parties, which are in the middle of fierce campaigns ahead of nationwide municipal elections on March 30, announced they would not play music at rallies Wednesday.

Turkish television also aired footage of university students in a canteen, banging their silverware on tables in a show of support for the Elvan family. Some high school and university student groups are calling for a boycott of classes Wednesday.

"A small kid is murdered and the killers are still loose. This is us standing up for our kid brother," said Bircan Birol, a 22-year-old member of the Student Collectives movement at Istanbul University. "There are pictures of Berkin up everywhere, and today we say: 'Our class is Berkin Elvan.' "

Recep Tayyip Erdogan, Turkey's fiery Prime Minister, has yet to mention the Elvan family in any of his daily campaign rallies. Erdogan is fighting hard to mobilize his ruling Justice and Development Party to continue its decade-long electoral winning streak in this month's municipal elections.

However, Abdullah Gul, the man who holds the largely symbolic post of Turkish President, personally called the grieving family Monday.

"The family was very grateful for the call. They asked (for) Mr President's help in finding out the security cam recordings of the incident, which, interestingly, couldn't be found so far," an official in Abdullah Gul's office wrote CNN in an e-mail, on condition of anonymity because of Turkish protocol.

"And they asked the help of Mr President for calm during the funeral -- and especially that the police shall not intervene. The President told them that he will talk to the governor especially to provide a smooth, calm and respectful funeral without any more bad scenes."

There was little to no visible police presence escorting the funeral procession on Wednesday. But as the sun began to set in Istanbul, police riot control vehicles began hosing down throngs of demonstrators with water cannons, sending thousands of people sprinting to escape clouds of tear gas.

Clashes also erupted in the port city of Izmir on Wednesday, as well as the Turkish capital Ankara.