A well-known Palestinian cabinet minister who frequently protested against Jewish settlements died Wednesday after a confrontation with Israeli forces at a demonstration in the West Bank, officials said. His death sparked outrage from the Palestinian leadership and an appeal by a U.N. envoy for a full Israeli probe.

The death of Ziad Abu Ein, 55, heightened tensions after months of Palestinian terrorist attacks, a 50-day war in the Gaza Strip and recent clashes set in motion by showdowns over a contested holy site in Jerusalem.

Palestinian Authority President Mahmoud Abbas announced three days of mourning and halted security coordination with Israel. Palestinian officials said an autopsy would be performed, and Israeli officials said one of their pathologists would attend.

Palestinian witnesses said Abu Ein was punched and kicked by Israeli border officers, who fired tear gas at the demonstrators. With numerous observers on the scene, video clips quickly began to circulate on news and social media sites.

One of Abu Ein’s assistants, who was with him during the confrontation, said his boss was punched in the throat, kicked and became overwhelmed by tear gas.

A Palestinian protester holds a Palestinian flag as he argues with Israeli soldiers during a protest against Jewish settlements near the West Bank city of Ramallah Wednesday. (Mohamad Torokman/Reuters)

Family members suspect that Abu Ein suffered a heart attack after being assaulted during the clashes.

The Israeli military said it is investigating. It said its “forces had attempted to halt the progress of the rioters” toward a nearby Israeli outpost by “using riot dispersal means.” Later on, Prime Minister Benjamin Netanyahu sent a message to the Palestinian Authority saying that the Israeli government also would investigate the incident.

An image posted by Sky News Arabia showed an Israeli soldier apparently grabbing the Palestinian politician by the throat. A video clip from Russia Today showed Abu Ein on the ground and clutching his chest behind a row of Israeli troops facing off against demonstrators near the West Bank village of Turmus Aya, where the march was held to protest Israeli land seizures.

Abu Ein was especially well known as a spokesman for Palestinians serving long sentences in Israeli prisons for terrorist attacks and political activities.

Mohammed Muhaisan, Abu Ein’s assistant, said the goal of the march had been to plant olive trees in the area. He said a large number of pro-Palestinian activists and international observers were present.

Muhaisan said two incidents occurred. Initially, he said, the minister exchanged harsh words with a border police officer, who grabbed him by the throat. A few minutes later, Muhaisan said, Abu Ein was subjected to a “karate chop” in the neck and was “hit with a punch or a helmet to his chest.”

The aide also said that a large quantity of tear gas was fired at the crowd, causing the minister to fall to the ground and turn rigid.

Palestinian minister Ziad Abu Ein, left, scuffles with an Israeli border policeman near the West Bank city of Ramallah Wednesday. (Reuters)

Muhaisan said Abu Ein was quickly taken by ambulance to a local clinic and then to a hospital in central Ramallah. The minister was unresponsive and could not be revived, Muhaisan said.

The U.N. special coordinator for the Middle East peace process, Robert H. Serry, said he was deeply saddened by the minister’s death and urged Israeli authorities to conduct a “prompt, thorough and transparent investigation into the circumstance of his death.”

Early reports by Israeli and Palestinian news media had said that Abu Ein was struck with a rifle butt.

A reporter for Israel’s Channel 10, Roy Sharon, posted a Twitter message saying that he did not see Abu Ein being struck with the butt of a rifle and that if he had been hit with a gun, the blow did not appear to be deliberate or significant. Sharon said he was standing near Abu Ein, who was appointed last year to lead opposition to Israeli settlements and the wall separating Israel from the West Bank.

Reut Mor, a spokeswoman for Yesh Din, an Israeli human rights organization whose members were present at the march, said about 100 villagers had been making their way with flags and with olive trees for planting. The protest coincided with the international Human Rights Day. The Israeli military placed the number of marchers at about 200.

“It was a quiet march. There was no violence, no stones. People were holding flags and olive trees when suddenly the protesters met almost as many soldiers,” Mor said. “They stood in front of us and started shooting tear gas and stun grenades even though there was no violence from our side.”

Palestinians frequently stage protests against Israeli settlements and unauthorized Jewish outposts in the West Bank, whose construction has continued despite objections from Washington and Israel’s allies in Europe.

In comments broadcast on Wednesday, Israeli Defense Minister Moshe Yaalon said that settlement construction should pick up in the future because the Obama administration — with which the Israeli leadership has had tense relations “won’t be around forever.”

Palestinian leaders condemned Abu Ein’s death and warned of major blows to already fraying relations with Israel.

Abbas, the Palestinian Authority president, called Abu Ein’s death a “barbaric act.” Hanan Ashrawi, a senior Palestinian official, demanded an “independent, neutral” investigation.

“Ziad was guilty of nothing more insidious than planting olive trees on Palestinian land that Israel was attempting to steal,” she said.

Saeb Erekat, the chief Palestinian peace negotiator, said, “The Israel government bears full responsibility for the killing of minister Abu Ein and the systematic crimes committed against the Palestinian people.”

“This new assassination will have severe consequences,” he added.

Palestinian officials said an autopsy would be carried out. Abu Ein suffered from diabetes and high blood pressure, his family said.

As family, friends and senior Palestinian officials gathered to mourn the minister, Abu Ein’s brother Ala’a Abu Ein said that it was unclear whether an autopsy would be performed but that his brother had been subjected to a heavy amount of tear gas.

Ala’a Abu Ein described his brother as one of the leaders of the second intifada, or popular uprising, a decade ago, which included suicide bombings inside Israeli territory and a harsh Israeli military crackdown on Palestinians.

The brother suggested that the Israelis had intended to seek out and assault Abu Ein at the demonstration.

Israeli reports said Abu Ein was a member of Fatah’s Revolutionary Council, which is also known as the Abu Nidal Organization and carried out terror attacks in the 1980s.

Abu Ein was given a life sentence in Israel in 1982 after being extradited from the United States over the killing of two Israelis in Tiberias in 1979. He was released in a prisoner swap in 1985.

During the second Palestinian uprising, he spent a year in detention in 2002 without being charged, the Associated Press reported.

Tensions have been high in the region since the summer war between Israel and Hamas in Gaza and over continuing disputes stemming from access to an area in Jerusalem known as the Temple Mount to Jews and the Noble Sanctuary to Muslims — a site holy to both faiths.

Clashes and bloodshed have occurred, including a Palestinian attack at a Jerusalem synagogue last month in which five people were killed, among them three American-born Israelis.

Eglash reported from Jerusalem. Brian Murphy in Washington contributed to this report.