Israeli riot police on Friday pushed and beat pallbearers at the funeral for slain Al Jazeera journalist Shireen Abu Akleh, causing them to briefly drop the casket in a shocking start to a procession that turned into perhaps the largest display of Palestinian nationalism in Jerusalem in a generation.

The scenes of violence were likely to add to the sense of grief and outrage across the Arab world that has followed the death of Abu Akleh, who witnesses say was killed by Israeli troops Wednesday during a raid in the occupied West Bank. They also illustrated the deep sensitivities over east Jerusalem - which is claimed by both Israel and the Palestinians and has sparked repeated rounds of violence.

Abu Akleh, 51, was a household name across the Arab world, synonymous with Al Jazeera's coverage of life under Israeli rule, which is well into its sixth decade with no end in sight. A 25-year veteran of the satellite channel, she was revered by Palestinians as a local hero.

Late Friday, the Palestinian public prosecutor said preliminary findings show Abu Akleh was killed by deliberate fire from Israeli troops. The prosecutor said the investigation would continue. Israel's military said earlier Friday that she was killed during an exchange of fire with Palestinian militants, and that it could determine the source of the shot that killed her.

At the funeral, thousands of people, many waving Palestinian flags and chanting: "Palestine! Palestine!" It was believed to be the largest Palestinian funeral in Jerusalem since Faisal Husseini, a Palestinian leader and scion of a prominent family, died in 2001.

Ahead of the burial, a large crowd gathered to escort her casket from an east Jerusalem hospital to a Catholic church in the nearby Old City. Many of the mourners held Palestinian flags, and the crowd began shouting, "We sacrifice our soul and blood for you, Shireen."

Shortly after, Israel police moved in, pushing and clubbing mourners. As the helmeted riot police approached, they hit pallbearers, causing one man to lose control of the casket as it dropped toward the ground. Police ripped Palestinian flags out of people's hands and fired stun grenades to disperse the crowd.

Abu Akleh's brother, Tony, said the scenes "prove that Shireen's reports and honest words ... had a powerful impact."

Al Jazeera correspondent Givara Budeiri said the police crackdown was like killing Abu Akleh again. "It seems her voice isn't silent," she said during a report.

East Jerusalem, home to the city's most important Jewish, Muslim and Christian holy sites, was captured by Israel in the 1967 Mideast war. It claims all of the city as its eternal capital and has annexed the eastern sector in a move that is not internationally recognized.

The Palestinians claim east Jerusalem as the capital of a future independent state. Israel routinely clamps down on any displays of support for Palestinian statehood. The conflicting claims to east Jerusalem often spill over into violence, helping fuel an 11-day war between Israel and Gaza militants last year and more recently sparking weeks of unrest at the city's most sensitive holy site.

Outside of prayers at the Al Aqsa Mosque, Israel rarely allows large Palestinian gatherings in east Jerusalem and routinely clamps down on any displays of support for Palestinian statehood.

Police said the crowd at the hospital was chanting "nationalist incitement," ignored calls to stop and threw stones at them. "The policemen were forced to act," police said. They issued a video in which a commander outside the hospital warns the crowd that police will come in if they don't stop their incitement and "nationalist songs."

Shortly before midnight, the Israeli police issued a second statement claiming that they had coordinated plans with the family for the casket to be placed in a vehicle, but that a "mob threatened the driver of the hearse and then proceeded to carry the coffin on an unplanned procession." It said police intervened "so that the funeral could proceed as planned in accordance with the wishes of the family."

The police claims could not be immediately verified. Earlier this week, Abu Akleh's brother had said the original plans were to move the casket in a hearse from the hospital to the church, and that after the service, it would be carried through the streets to the cemetery.

Al Jazeera said in a statement that the police action "violates all international norms and rights."

"Israeli occupation forces attacked those mourning the late Shireen Abu Akhleh after storming the French hospital in Jerusalem, where they severely beat the pallbearers," it said. The network added that it remains committed to covering the news and will not be deterred.

White House press secretary Jen Psaki called the images "deeply disturbing."

The focus should be "marking the memory of a remarkable journalist who lost her life," Psaki said. "We regret the intrusion into what should have been a peaceful procession."

During a Rose Garden event, U.S. President Joe Biden was asked whether he condemns the Israeli police actions at the funeral, and he replied: "I don't know all the details, but I know it has to be investigated."

U.N. Secretary-General Antonio Guterres "was deeply disturbed by the confrontations between Israeli security forces and Palestinians gathered at St. Joseph Hospital, and the behavior of some police present at the scene," according to a statement from his deputy spokesman, Farhan Haq.

Israeli police eventually escorted the casket in a black van, ripping Palestinian flags off the vehicle as it made its way to the church.

"We die for Palestine to live!" crowds chanted. "Our beloved home!"

Later, they sang the Palestinian national anthem and chanted "Palestine, Palestine!" before her body was buried in a cemetery outside the Old City.

Her grave was decorated with a Palestinian flag and flowers. The Palestinian ambassador to the U.K., Husam Zomlot, and Al Jazeera's bureau chief, Walid Al-Omari, placed flowers on the grave.

Salah Zuheika, a 70-year-old Palestinian, called Abu Akleh "the daughter of Jerusalem," and said the huge crowds were a "reward" for her love of the city.

"We already miss her, but what had happened today in the city will not be forgotten," he said.

Abu Akleh was a member of the small Palestinian Christian community in the Holy Land. Palestinian Christians and Muslims marched alongside one another Friday in a show of unity.

She was shot in the head Wednesday morning during an Israeli military raid in the West Bank town of Jenin.

In preliminary findings released late Friday, the Palestinian public prosecutor disputed the military's claim that Abu Akleh was caught in crossfire. The prosecutor said that at the time she was shot, Israeli troops were the only ones firing, with the nearest forces about 150 meters (yards) away.

The report said Abu Akleh was shot deliberately, citing traces on the tree next to where she was hit which, the prosecutor argued, indicated that the shots were fired directly at her. It said the shooting continued after she was hit, hindering first aid attempts.

Earlier Friday, the Israeli military said it could not could not determine who was responsible for her death without a ballistic analysis.

"The conclusion of the interim investigation is that it is not possible to determine the source of the fire that hit and killed the reporter," the military said.

Israel has called for a joint investigation with the Palestinian Authority and for it to hand over the bullet for forensic analysis to determine who fired the fatal round. The PA has refused, saying it will conduct its own investigation and send the results to the International Criminal Court, which is already investigating possible Israeli war crimes.

Reporters who were with Abu Akleh, including one who was shot and wounded, said there were no clashes or militants in the immediate area. All of them were wearing protective equipment that clearly identified them as reporters.

The PA and Al Jazeera, which has long had a strained relationship with Israel, have accused Israel of deliberately killing Abu Akleh. Israel denies the accusations.

Rights groups say Israel rarely follows through on investigations into the killing of Palestinians by its security forces and hands down lenient punishments on the rare occasions when it does. This case, however, drew heavy scrutiny because Abu Akleh was well-known and also a U.S. citizen.

Palestinians from in and around Jenin have carried out deadly attacks in Israel in recent weeks, and Israel has launched near daily arrest raids in the area, often igniting gunbattles with militants.

Israeli troops pushed into Jenin again early Friday, sparking renewed fighting.

The Palestinian Health Ministry said 13 Palestinians were wounded. The Israeli military said that Palestinians opened fire when its forces went in to arrest suspected militants. Police said a 47-year-old member of a special Israeli commando unit was killed.

From The Associated Press