A Palestinian Authority minister died shortly after a confrontation with IDF soldiers during a protest on Wednesday in the West Bank, a Reuters photographer who witnessed the incident and a medic said.

According to IDF sources, the military believes that his death was a result of a heart attack.

The IDF said initial estimates indicated there was no direct physical confrontation between the soldiers and the PA minister, however, the incident was still being investigated.

The IDF was due to release further details on the circumstances of the incident shortly.

Ziad Abu Ein, a PA minister without portfolio, was rushed by ambulance from the scene, in the village of Turmusiya, but died en route to the nearby city of Ramallah.

According to Palestinian officials, the Fatah official sustained critical injuries after an IDF soldier struck him with a helmet in the chest and from the inhalation of tear gas fired in the area, Palestinian news agency Ma’an reported.

Witnesses told Reuters that about 100 foreign and Palestinian activists with the PA Committee to Resist Settlements and the Wall, the government-run protest organization that Abu Ein headed, were on their way to plant trees and protest near an Israeli settlement when they were stopped at an improvised checkpoint.

A group of around 15 Israeli soldiers fired tear gas at the protesters and a scuffle began, Reuters reported.

According to the Reuters photographer, Abu Ein was struck by a hand to the neck during an altercation with two of the soldiers, and was rushed away in an ambulance shortly afterwards.

Palestinian President Mahmoud Abbas, in a statement, called Abu Ein’s death “a barbaric act which we cannot be silent about or accept”. Announcing three days of national mourning, Abbas said he would take “necessary steps” after an investigation.

Palestinians in Ramallah closed shops in protest at the minister’s death and youths threw stones at Israeli soldiers guarding a Jewish settlement outside the city, Palestinian security sources said.

Following the summer war with Hamas in Gaza, tensions have risen in past weeks over access to Jerusalem’s Temple Mount complex – a holy site to both Muslims and Jews – triggering Palestinian street protests.

Yaakov Lappin and Noam Amir contributed to this report.