A Palestinian Cabinet minister died Wednesday as he and other protesters clashed with Israeli troops in the West Bank.
It is unclear what killed minister Ziad Abu Ein, who was taking part in a march of several hundred Palestinians intending to plant olive branches.
Palestinian President Mahmoud Abbas has declared three days of mourning and called the incident "brutal" and barbaric. He pledged to "take the necessary measures" after an investigation.
The Israeli army says Israeli and Jordanian pathologists will oversee an autopsy on Abu Ein's body to determine what caused his death. Israel also proposed a joint investigation with the Palestinians.
Witnesses say protesters were confronted by Israeli troops who fired tear gas and hit some of the protesters with riffle butts, including Abu Ein in the chest. But the Associated Press reported that one of its photographers and an Israeli reporter said they did not see Abu Ein hit with a rifle butt.
The U.S. State Department offered condolences to Abu Ein's family, and called for a swift, fair and transparent investigation. U.N. Secretary-General Ban Ki-moon also urged Israeli authorities to conduct a "swift and transparent" investigation.
Abu Ein, who was 55 years old, led a Palestinian Authority department dealing with Israeli settlements.
In 1981, he was extradited from the United States to Israel and sentenced to life in prison due to the killing of two Israelis. He was released in a prisoner swap in 1985.
His death comes after an escalation in Israeli-Palestinian tensions largely related to the Temple Mount, a Jerusalem holy site known to Muslims as the al-Aqsa Mosque. More than a dozen Israelis and Palestinians were killed in the violence.