Photographs showed Ziad Abu Ein (left) tussling with an Israeli soldier at the protest
A Palestinian minister has died after a confrontation with Israeli troops at a protest in the West Bank.
Palestinian medics told the BBC that Ziad Abu Ein had died as a result of inhaling tear gas during the incident near the village of Turmusaya.
But several witnesses said the minister had been hit and shoved by soldiers. One said he had been hit in the chest by a tear-gas canister fired by them.
The Israeli military said it was looking into the reports.
The incident comes at a time of rising tensions between in the region.
In recent weeks, 11 Israelis were killed by Palestinians, including five stabbed and shot at a synagogue in Jerusalem. Thirteen Palestinians were also killed, among them several assailants.
'Barbaric act'
Mr Abu Ein, a minister without portfolio, was among dozens of foreign and Palestinian activists who took part in a protest on Tuesday morning against land confiscations organised by the government-run Committee to Resist Settlements and the Wall.
Protesters had planned to plant olive tree saplings on a patch of land they fear will be annexed by Israel
As they approached the land, the protesters - led by Mr Abu Ein - were stopped by Israeli soldiersThey had planned to plant olive tree saplings on a patch of land near the Jewish settlement of Shiloh, which Palestinians believe has been earmarked for annexation by Israel.
In the course of the protest, they came into confrontation with a group of about 15 Israeli soldiers.
Mahmoud Aloul, a leading member of Palestinian Authority President Mahmoud Abbas's Fatah movement, told the Associated Press the soldiers had fired tear gas at the protesters and had beaten some of them with rifle butts.
At one point, Mr Abu Ein was hit by a tear gas canister, Mr Aloul said.
Kevin Connolly says there are conflicting reports about what happened
The Reuters photographer said he had seen Mr Abu Ein being struck by a hand to the neck during an altercation with two of the soldiers. An AFP news agency photographer said the minister had been hit in the chest.
Photos of the incident showed Mr Abu Ein lying unconscious before he was removed from the scene in an ambulance. He died before reaching hospital in the nearby city of Ramallah.
The director of the Ramallah hospital told the AFP news agency that Mr Abu Ein had been "martyred after being beaten in the chest".
There are reports that Mr Abu Ein had a health condition that may have contributed to his death.
The BBC's Kevin Connolly in Jerusalem says Palestinians are likely to see the exact cause of death as a secondary issue, and it will serve to sharpen political tensions.
President Abbas condemned "the brutal assault" that led to Mr Abu Ein's "martyrdom", calling it a "barbaric act that cannot be tolerated or accepted".
"We will take the necessary measures after the results of the investigation into the incident," he added.
A senior Palestinian official said the Palestinian Authority would halt security co-ordination with Israel.
