Jerusalem (AFP) - Israeli police made dozens of arrests overnight as violent protests over the murder of a Palestinian teenager by suspected Jewish extremists swept Arab Israeli towns into Sunday.
The military meanwhile carried out 10 air strikes on Gaza in response to persistent rocket fire into southern Israel as hopes faded of a renewed truce with its Islamist foe Hamas.
Violence which rocked annexed Arab east Jerusalem for four straight days after the kidnap and murder of the Palestinian teenager on Wednesday, spread to half a dozen Arab towns in Israel on Saturday.
The initial results of a post-mortem found that the 16-year-old was likely burned alive in what many Palestinians believe was a revenge killing by Jewish extremists after the kidnap and murder of three Israeli teenagers in the occupied West Bank last month.
"Around 35 people were arrested overnight, almost half of them minors," police spokeswoman Luba Samri told AFP.
Of those, 22 were arrested in and around the northern city of Nazareth, the most populous Arab town in Israel.
The rest were arrested in Taibe in the north and the Triangle region around Umm el Fahm, an Islamist stronghold northeast of Tel Aviv, where clashes continued into Sunday, Samri added.
"We are demonstrating against this incitement to hatred by Israelis online, who are saying 'death to Arabs'," one demonstrator in the Triangle town of Qalansuwa told army radio.
Israel police confirmed they had opened an internal investigation into allegations of police brutality following the publication of a video showing border police beating a handcuffed detainee.
The video was released as news emerged that a 15-year-old Palestinian with US citizenship had been badly beaten while in police custody in east Jerusalem, triggering condemnation from the US State Department.
He was due to appear in court on Sunday morning.
- Rockets on Beersheva -
The latest round of violence began on June 12 with the kidnap and subsequent murder of three Israeli teenagers in an attack Israel blamed on Hamas.
The kidnapping triggered a major army crackdown on the West Bank, with more than 400 Palestinians arrested, two-thirds of them Hamas members, and six people killed in clashes sparked by the arrests.
Two days after their bodies were found, a Palestinian of similar age from east Jerusalem was kidnapped and killed, sparking clashes which on Saturday spread to Israeli Arab towns.
Tensions have also been high in and around Gaza, where Hamas has its stronghold, with militants responding to the West Bank crackdown with rocket fire on southern Israel.
The air force has hit back with almost nightly strikes, which have killed three Palestinian militants so far.
On Saturday, militants fired 15 rockets and mortar rounds at Israel, two of which targeted the southern city of Beersheva some 40 kilometres (25 miles) from the Palestinian territory, police said.
It was the first time the city had been targeted since the army's last major operation in Gaza, named Pillar of Defence, in November 2012.
The air force responded with new strikes early on Sunday, none of which caused casualties.
"Following constant rocket fire at Israeli communities in the south, IAF (Israel Air Force) aircraft targeted 10 terror sites in the central and southern Gaza Strip, including concealed rocket launchers and a weapon manufacturing facility," a statement said.
Also on Sunday, the army said it had arrested a Palestinian in the flashpoint southern West Bank city of Hebron, whom the Israeli media suggested was somehow linked to the kidnap and murder of the three teenagers.
Israel has named two Hamas militants from Hebron as the prime suspects -- Marwan Qawasmeh and Amer Abu Eishe. Both remain at large.