Israeli police have arrested a group of Jewish extremists in connection with the kidnap and murder of a Palestinian teenager who was burned to death in a suspected revenge killing.
The brutal killing on July 2 has triggered four days of violent clashes which began in east Jerusalem and have since spread to more than half a dozen Arab towns in Israel, with hordes of angry protesters hurling stones at Israeli riot police.
"Apparently the people arrested in relation to the case belong to an extremist Jewish group," an official said, speaking on condition of anonymity.
The website of Haaretz newspaper said six people had been arrested, but details of the case have been subjected to a strict gag order.
Earlier, police acknowledged for the first time "indications that the background to the killing was nationalistic".
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It followed days of growing suspicion that Wednesday's murder was carried out by extremist Jews in revenge for last month's abduction and murder of three Israeli teenagers in the occupied West Bank.
Tensions continued to rise in the south with Gaza militants firing another nine rockets over the border, despite a night of 10 air strikes.
Israeli Prime Minister Benjamin Netanyahu has urged his cabinet to keep a cool head over how to handle tensions in and around Gaza.
Overnight, Israel police arrested 35 people as violent protests over the teenager's murder swept more than half a dozen Arab Israeli towns.
The violence exploded as a top Palestinian legal official confirmed that initial findings from the post-mortem showed there was smoke in the lungs of 16-year-old Mohammed Abu Khder, indicating he was still alive when he was set on fire.
The grisly murder has sparked shock, disgust and an outpouring of condemnation from both Israeli and Palestinian leaders.
But until Sunday, police said they were unsure of the motive for the killing, contributing to the rising tensions.
"Around 35 people were arrested overnight, almost half of them minors," police spokeswoman Luba Samri told AFP.
In a related development, a Jerusalem court freed a Palestinian American teenager, who was allegedly beaten in police custody, to house arrest for nine days pending an investigation into stone-throwing allegations.
Tariq Abu Khder, 15, a cousin of the murdered teen, was arrested on Thursday in the east Jerusalem neighbourhood of Shuafat as clashes raged, and his parents said he was badly beaten in police custody.
A day after his arrest, a video surfaced on YouTube showing Israeli border police beating and kicking a handcuffed semi-conscious figure on the ground, before dragging him away.
The US government said it was "profoundly troubled" by the report, prompting the Israeli justice ministry's police investigations department to begin an urgent investigation.
