A Palestinian teenager killed in Jerusalem was burned alive, first post mortem examination findings quoted by the Palestinian attorney-general say.
"The direct cause of death was burns as a result of fire," Mohammed al-A'wewy was quoted as saying.
Israeli authorities say the circumstances surrounding the death of Mohammad Abu Khdair, 16, are unclear.
His death followed the abduction and murder of three young Israelis, with violent clashes spreading overnight.
The post mortem examination on Mohammad Abu Khdair was carried out by Israeli doctors, with Saber al-Aloul, the director of the Palestinian forensic institute, in attendance.
The Palestinian official news agency Wafa quoted the attorney-general as saying that Mr Aloul had reported fire dust in the respiratory canal, meaning the victim had "inhaled this material while he was burnt alive".
Mohammad Abu Khdair, who had also suffered a head injury, had burns to 90% of the body, it was reported.
The findings have not been officially released.
Mohammad Abu Khdair's family believe he was killed in revenge for the murders of the three Israeli teenagers.
The bodies of Naftali Frenkel and Gilad Shaar, both aged 16, and 19-year-old Eyal Yifrach were found on 30 June. Their funerals were held on Wednesday.
Thousands attended Mohammad Abu Khdair's funeral on Friday near the family's home in the Shufat district of East Jerusalem.
Hundreds of Palestinian youths clashed with Israeli police in East Jerusalem before and after the funeral.
The clashes continued overnight in the West Bank and spread to Israeli-Arab towns in northern Israel.
Israeli police spokeswoman Luba Samri said protesters burned tyres and hurled rocks. Disturbances were reported in Taibe and Tira.
Police responded with tear gas and stun grenades and more than 20 people were arrested.
Clashes were also reported in the central town of Qalansawe overnight, with Jewish drivers attacked and some cars torched.
Haaretz reported that some 50 Palestinians and 13 policemen were hurt in clashes, which it said had spread to all of East Jerusalem's districts.
It quoted Foreign Minister Avigdor Lieberman as saying that rioters "do not belong in the state of Israel - and until that is resolved, their place is in jail".
Israeli officials handed the body of Mohammad Abu Khdair to his family on Friday morning.
He was seen being forced into a car in Shufat early on Wednesday and his body was later found in West Jerusalem.
The killing came after the bodies of the three Israeli seminary students were found near the city of Hebron on Monday, two-and-a-half weeks after they were abducted.
Israeli Prime Minister Benjamin Netanyahu blamed their deaths on Hamas. It has denied any involvement.
Mr Netanyahu also condemned the killers of the Palestinian teenager and vowed to bring the perpetrators to justice.