A Palestinian teenager who was found dead in Jerusalem last week in an apparent revenge killing was burned to death, according to an autopsy report released Saturday. The killing incited violent clashes in Palestinian towns in Israel, which created tense standoffs with Israel Defense Force officers. 

Sixteen-year-old Palestinian teen Mohammed Abu Khdeir, who was killed Wednesday, suffered burns on "90 percent of his body," according to Palestinian Attorney General Abdelghani al-Owaiwi. 

"The results show he was breathing while on fire and died from burns and their consequences," al-Owaiwi told The Associated Press. 

The Palestinian teen's body was found in a forest near his home. Palestinians accused right-wing Israeli extremists of killing the teen as an act of revenge to avenge the murders of three Israeli teens who were abducted in the West Bank then found dead last week.  

An investigation into the killings is underway, and Israel says they do not yet know who killed the Palestinian teen.  

Israeli Prime Minister Benjamin Netanyahu and other Israeli leaders have condemned the revenge killing, and Netanyahu said he will bring the killers to justice.  

Meanwhile, fighting continued on Saturday on the southern border of the Gaza Strip. According to the Israeli military, militants in Gaza fired at least 10 rockets into Israel Saturday, injuring a soldier and destroying parts of Israeli buildings and infrastructure. 

Israel launched several retaliatory air strikes into Gaza Saturday night in an attempt to destroy Hamas' rocket-launching sites. 

Protests broke out in Palestinian neighborhoods after news spread of the boy's death Wednesday. On Friday, riots ensued as thousands of Palestinians attended the boy's funeral in Jerusalem. 

Clashes spilled into Arab towns in northern Israel Saturday. Protesters threw rocks at cars, burned tires and threw rocks and firebombs at police officers. IDF officials retaliated by using tear gas and stun grenades. 

Protesters also pulled an Israeli Jew out of a car in the town of Qalansawe and set the car on fire. The driver was not injured, according to The AP. 

The protesters in Jerusalem also used an electric saw to deface a light rail that connects the heavily Arab east with the predominantly Jewish area of West Jerusalem. 

More than 20 people were arrested in the riots. 

While Israeli Arabs hold citizenship rights in Israel, they often face discrimination and identify with the Palestinians in Gaza and the West Bank. 

Tensions were initially raised when the three Israeli teens were abducted in the West Bank on June 12, which incited the largest Israeli military offensive in the West Bank in a decade. The extensive manhunt ended with the discovery of the bodies of the teens early this week. 

The Associated Press also reported that Abu Khdeir's 15-year-old cousin, who is a U.S. citizen who goes to school in Florida, was beaten by police during the clashes Thursday. 

The parents of the 15-year-old, named Tariq, said their son was detained but has since been treated at an Israeli hospital. 

An Israeli police spokeswoman said that Tariq was beaten by the Israeli military because he had resisted arrest and attacked police officers. He also hurled stones at police, along with six other protesters, some of whom had knives. The spokeswoman said that several officers were hurt in the protest. 

However, Tariq's father insisted that his son was not involved in the clash. 

The tension between Israel and the Palestinian territory has continued during the clashes. Palestinian militants fired 150 rockets into southern Israel, and Israel responded by firing air strikes on more than 70 Hamas targets in Gaza.