Did Palestinian politician die, or was he killed?

RAMALLAH, West Bank -- Israeli and Palestinian pathologists disagreed Thursday on whether a blow to the body or a bad heart was the main cause of death of a Palestinian Cabinet minister who collapsed shortly after scuffling with Israeli troops during a West Bank protest.

Palestinian doctors said Ziad Abu Ain died from a blow, not natural causes. Israeli doctors said the 55-year-old died from a blockage of the coronary artery due to arterial bleeding that could have been caused by stress.

Abu Ain's death, followed by the Palestinian autopsy findings, could further inflame tensions between Israel and the Palestinians.

Palestinian President Mahmoud Abbas has said Abu Ain was the victim of a crime and of a "barbaric act" and decreed three days of mourning.

Anticipating Palestinian protests after Abu Ain's funeral later Thursday, the Israeli military has sent troop reinforcements to the West Bank. Earlier Thursday, several dozen Palestinian stone throwers clashed with Israeli troops in the West Bank city of Hebron.

Abu Ain died Wednesday, shortly after a West Bank confrontation between Palestinian protesters and Israeli soldiers that included pushing and shoving. At one point, a member of Israel's paramilitary border police grabbed Abu Ain by the throat and pushed him. Troops also fired tear gas during the confrontation.

Several minutes after the scuffle, Abu Ain collapsed to the ground, clutching his heart. He received first aid and was evacuated, but died en route to a hospital.

An autopsy was conducted later Wednesday by Palestinian, Jordanian and Israeli pathologists.

Palestinian pathologist Saber Aloul said, "the cause of death was a blow, and not natural causes."

Palestinian Health Minister Jawad Awad said that "the results of the autopsy show that the ones who killed the martyr Ziad Abu Ain are the Israeli occupying forces."