JERUSALEM -- Initial autopsy findings that an Arab teenager found dead after he was kidnapped in East Jerusalem was burned alive added Saturday to a growing sense that Israeli-Palestinian tensions have reached explosive levels.
Protests over the death of Muhammad Abu Khdeir, 16, spread from East Jerusalem to Arab communities inside Israel. Youths burned tires and hurled stones in Nazareth, the largest Arab city in Israel, in Arab towns northeast of Tel Aviv, and along a major east-west highway flanked by Arab villages.
The apparent beating by Israeli police of an Arab-American teen from Florida who is a cousin of Abu Khdeir and was visiting family in East Jerusalem also drew criticism from the Obama administration.
State Department spokeswoman Jen Psaki said the United States was profoundly troubled by reports that 15-year-old Tarik Abu Khdeir, a high school sophomore from Tampa, was severely beaten while in police custody.
We are calling for a speedy, transparent and credible investigation and full accountability for any excessive use of force, Psaki said.
The Palestinian Authoritys attorney general, Muhammad Abdel Ghani al Aweiwi, said in a statement that an autopsy showed that Muhammad Abu Khdeir, who was abducted early Wednesday outside a mosque in East Jerusalem, died from burns and their complications.
The post mortem examination of Abu Khdeirs body found soot in the area of the breathing airways, windpipes and .lungs, which indicates inhalation of this substance during the burning when he was alive, the statement said.
Burns of varying degrees were found on 90 percent of the youths body, and his head was bruised, according to the statement. Specimens were taken from the corpse for further laboratory examination.
A spokeswoman for the Israeli health ministry and a police spokesman said they had no knowledge of the preliminary findings. The autopsy was performed at Israels forensic institute with the participation of the chief Palestinian forensic pathologist, and final results have yet to be released.
But the Palestinian attorney generals statement, which was released late Friday, seemed likely to exacerbate what already had become a rapidly deteriorating security situation in the wake of the kidnappings and murders of three Israeli teenagers, who disappeared June 12 and whose bodies were found hidden in a field in the West Bank on Monday.
Police say they are still trying to determine whether Abu Khdeirs kidnapping and murder hours after the three Israeli teens joint funeral was retaliation for the Israelis deaths. But even without that official finding, the discovery of his body in a wooded area of Jerusalem surrounded by Jewish neighborhoods set off a wave of rioting in Arab East Jerusalem, where stone-throwing youths have confronted Israeli police in several neighborhoods.
The unrest spread on Saturday to Arab towns in Israel, with masked youths setting up barricades of burning tires and hurling stones at police, who responded with stun grenades and tear gas.
After a meeting with security chiefs, Prime Minister Benjamin Netanyahu ordered a crackdown on the rioters, Israeli media reported.
Netanyahu has condemned the killing of Abu Khdeir, calling it a despicable murder.
On Saturday, the Israeli Justice Ministry said it also would investigate the severe beating of Tarik Abu Khdeir during street clashes on Thursday.
A video circulated on the Internet shows two Israeli border police officers repeatedly punching, kicking and stomping on the youth as he lies on the ground, then carrying him off with his arms cuffed behind his back to a group of Israeli undercover officers disguised as masked protesters. Pictures of the youths swollen and disfigured face were also posted on the Internet.
Tarik Abu Khdeirs father, Salahedeen Abu Khdeir, told McClatchy in a telephone interview, that he and his son were on a month-long visit from Tampa to East Jerusalem to see relatives.
Salahdeen Abu Khdeir said that his son had gone outside to watch the confrontations in the neighborhood when he was assaulted by police and beaten senseless. He said his son had not participated in any stone-throwing, and had been held for more than six hours without medical treatment before being transferred to a hospital.
The teenager is currently in detention, awaiting a court hearing on Sunday, his father said.
Micky Rosenfeld, a police spokesman, said that the video was edited and failed to show the entire incident, in which six masked Palestinians, three of them armed with knives, had resisted arrest and assaulted the officers.
The circumstances of the case are being reviewed, he said.
Tensions also remained high on the border with the Gaza Strip, after militants fired more rockets into Israel, causing no casualties. Israel responded with air strikes, hitting three Hamas terror targets, in the southern Gaza Strip, the army said.
Egypt is working to mediate a cease-fire between Hamas and Israel after three weeks of cross-border hostilities triggered by the kidnapping and killing of the Israeli teens, which Israel blamed on Hamas.