* Erdogan criticises dead teenager and his family
* Comments likely to stir more tension before local polls
* Boy's death sparked anti-government protests in Turkey
Turkish Prime Minister Tayyip Erdogan said a teenager who died this week after sustaining a head injury in anti-government protests last summer was linked to "terrorist organisations", in comments likely to fan political tensions.
The death of 15-year-old Berkin Elvan on Tuesday after nine months in a coma sparked Turkey's worst unrest since nationwide anti-government demonstrations last June, compounding Erdogan's woes as he battles a graft scandal that has become one of the biggest challenges of his decade in power.
Erdogan made his remarks, his first about Elvan, late on Friday at a campaign rally in southeast Turkey ahead of nationwide municipal elections on March 30.
"This kid with steel marbles in his pockets, with a slingshot in his hand, his face covered with a scarf, who had been taken up into terror organisations, was unfortunately subjected to pepper gas," Erdogan told a crowd of supporters in a speech broadcast on state-run TRT-Haber news channel.
"How could the police determine how old that person was who had a scarf on his face and was hurling steel marbles with a slingshot in his hand?"
Elvan, then 14, got caught up in street battles in Istanbul on June 16 while going to buy bread for his family. He was hit in the head by what is believed to be a police gas canister, slipped into a coma and became a rallying point for government opponents, who held regular vigils at the hospital where he lay in intensive care.
After his death, riot police used water cannon, tear gas and rubber pellets to disperse tens of thousands of protesters who took to the streets of Turkey's largest cities chanting "Tayyip! Killer!" and "Everywhere is Berkin, everywhere is resistance."
At campaign rallies in the past few days, Erdogan has accused a coalition of "anarchists, terrorists and vandals" as well as opposition parties and an influential U.S.-based Islamic cleric of orchestrating the unrest to undermine him.
Using harsh words unlikely to soothe public anger, Erdogan - who unlike President Abdullah Gul and other public figures did not send condolences to Elvan's family - criticised the boy's parents and suggested he had not really gone to buy bread.
"His mother says 'my son's killer is the prime minister'. I know love, fondness for one's child, but I could not understand why you threw steel marbles and carnations into your son's grave," Erdogan said at his election campaign rally.
Elvan's family are Alevis, a religious minority in mainly Sunni Muslim Turkey which espouses a liberal version of Islam and has often been at odds with the Islamist-rooted government.
Erdogan contrasted Elvan's death with that of 22-year-old Burakcan Karamanoglu, who was shot dead in Istanbul on Wednesday after an apparent standoff with a group of anti-government protesters. Erdogan has blamed his death on a far-leftist group.
"Our son Burakcan was martyred just three months after coming back from his military service. Burakcan was not carrying a slingshot or a gun," Erdogan said.
The fathers of Elvan and Karamanoglu spoke together on Friday and made a joint appeal on television to Turks to remain calm and not to use their sons' deaths for political ends.
Erdogan, who has presided over a decade of rising living standards, remains Turkey's most popular politician and his AK Party is expected to outstrip its rivals in the local polls.
But critics say Erdogan is becoming increasingly authoritarian and intolerant, pointing to moves to tighten government control of the judiciary and of the Internet.
Erdogan says the moves are necessary to counter what he sees as attempts by a former ally-turned-foe, U.S.-based Islamic cleric Fethullah Gulen, to unseat him.
Gulen's many followers in Turkey's police and judiciary are widely believed to be behind a series of leaked audio recordings purportedly exposing graft and other malpractices in Erdogan's inner circle. Gulen denies any involvement in the scandal.