Palestinian Attorney General Abdelghani al-Owaiwi said initial results show that 16-year-old Palestinian Mohammed Abu Khdeir, whose death Wednesday had sparked large protests in his east Jerusalem neighborhood, suffered burns on "90 percent of his body."
"The results show he was breathing while on fire and died from burns and their consequences," al-Owaiwi said.
Tensions also remained high on Israel's reinforced southern border with the Gaza Strip. Gaza militants fired at least ten rockets at Israel Saturday, injuring a soldier lightly and causing some damage to infrastructure, the military said.
It said it had launched several airstrikes in Gaza overnight against sites used by the militant group Hamas.
Abu Khdeir's charred body was found in a forest after he was seized near his home. Palestinians immediately accused Israeli extremists of killing him to avenge the deaths of three Israeli teens who had been abducted and killed in the West Bank. Israeli police said an investigation is still underway and they have not yet determined who killed the boy or why.
Israeli leaders have widely condemned the killing of the Palestinian youth, and Prime Minister Benjamin Netanyahu vowed those responsible would be brought to justice.
Palestinians took to the streets in protests after news of the boy's death on Wednesday and clashed with police in east Jerusalem. Riots erupted in east Jerusalem Friday as thousands of Palestinians massed for the boy's burial.
The violence spread to Arab towns in northern Israel early Saturday, with protesters throwing rocks at passing cars, burning tires and lobbing rocks and firebombs at police, who responded with tear gas and stun grenades, Israeli police spokeswoman Luba Samri said.
Near the town of Qalansawe, protesters also pulled over a car driven by an Israeli Jew, pulled him out and set the vehicle on fire, Samri said. The driver was not injured.
More than 20 people were arrested before the unrest subsided in the afternoon, she said.
Israeli Arabs, unlike Palestinians in the West Bank and Gaza Strip, hold citizenship rights. But they often face discrimination and mostly identify with the Palestinians.
Palestinian protesters in Jerusalem also used an electric saw to damage the light rail that connects the heavily Arab populated eastern sector of the city with the mostly Jewish West, Samri said.
The chaos began after three Israeli teenagers, one of whom was a U.S. citizen, were abducted in the West Bank on June 12, sparking a huge manhunt that ended with the gruesome discovery of their bodies earlier this week.
In a separate incident, relatives told The Associated Press that Abu Khdeir's 15-year-old cousin Tariq, a U.S. citizen who goes to school in Florida, was beaten by police during clashes on Thursday ahead of the funeral. The U.S. Consulate had no immediate comment on the report.
His parents, Suha and Salah, said Tariq was detained but had been treated at an Israeli hospital.
Samri, the Israeli police spokeswoman, said that Tariq Abu Khdeir had resisted arrest and attacked police officers. He was detained with a slingshot in his possession used to hurl stones at police, along with six other protesters, including some armed with knives, she said, adding that several officers were hurt in that specific protest, one of many that day.
Tariq's father said he witnessed his son's arrest and insisted the boy was not involved in the violence.
Israel launched a massive crackdown on the Islamic militant group Hamas after the abduction of the Israeli teens, while retaliatory Palestinian rocket attacks and Israeli airstrikes intensified. The military says Palestinian militants have fired more than 150 rockets at southern Israel, and it has responded with airstrikes on more than 70 targets in Gaza.
Associated Press writer Mohammed Daraghmeh in Ramallah, West Bank contributed to this report.
Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.