Relatives mourn the deaths of Palestinians shot dead by Israeli troops, at a hospital in the West Bank city of Ramallah August 26, 2013. (MOHAMAD TOROKMAN/REUTERS)

Palestinian leaders said peace negotiations are under threat after Israeli security forces fatally shot three Palestinian men during an early-morning clash Monday in the Qalandiya refugee camp here.

It was one of the deadliest incidents in the West Bank since 2009, when three Palestinians were killed in Nablus after a standoff with Israeli forces. In addition to the three dead in the Monday incident, 15 people were wounded and six were in critical condition in Ramallah hospitals, according to Palestinian officials.

A senior member of the Palestinian Authority said a gathering scheduled for Monday as part of the U.S.-led peace negotiations was postponed in protest of the killings.

Citing a promise to keep initial talks secret, Israeli officials declined to comment on whether any meeting was scheduled or canceled.

State Department spokeswoman Marie Harf told the Reuters news agency, “I can assure you that no meetings have been canceled.” She said, “The parties are engaged in serious and sustained negotiations.”

The Monday incident began when members of the Israeli border patrol, in civilian cars and clothing, arrived before dawn in the Qalandiya refugee camp at the southern edge of Ramallah to arrest a “terror operative,” according to military officials.

As the officers were searching for the man named Youssef Khatib, who was recently released from prison, groups of young men who had been alerted to their presence arrived to confront them, followed by Israeli soldiers who came to assist the border patrol, according to witnesses and Israeli military spokesmen.

The Israeli military said the Palestinians attacked the Israeli security forces using cement blocks and rocks, and posed an imminent threat to their lives. “Large, violent crowds such as this, which significantly outnumber security forces, leave no other choice but to resort to live fire in self-defense,” said Lt. Col. Peter Lerner, a spokesman for the Israel Defense Forces.

Palestinians said the Israelis acted with excessive force.

Video from the scene shows two Israeli jeeps slowly going down a street in Qalandiya as men on rooftops bombard the vehicles with cement blocks, but it was not clear whether the rock-throwing occurred before or after the killings.

At the funeral for the three dead, senior Palestinian leaders and angry residents said Israel provoked the attack by arriving in the refugee camp in the morning, when people were heading to work, school and mosque.

Israeli military officials said the attempt to arrest the suspect was a “nighttime incursion” that led to a riot. Video showed, and witnesses said, that the violence occurred after sunrise.

“It is clear to us that the occupiers do not want a peace process, and so the Israelis create these kinds of incidents,” said Mahmoud al-Aloul, the former governor of Nablus district and a member of the central committee of the Fatah political party.

As members of the al-Aqsa Martyrs Brigades fired automatic weapons in the air, a local Muslim cleric told the mourners that “the Israelis don’t want peace. They want to shed our blood.”

Later, Nabil Abu Rudeineh, a spokesman for Palestinian Authority President Mahmoud Abbas, told reporters that “the continued criminal acts by the Israelis, alongside the continued settlement construction, expose the true intentions of Israel’s government and the actions it takes to foil the peace talks.”

Rudeineh called on U.S. officials to intervene “to thwart the collapse of the negotiations.”

Omar Hammad, a resident of Qalandiya who said he witnessed Monday’s events, said Israeli security forces shot one victim in the chest from the back of a jeep and another while he was on a rooftop.

“I have seen many incursions by Israeli soldiers into our neighborhood,” Hammad said. “It seemed that this time they came to kill.”

Fadi Matteer, 27, said he was entering Qalandiya when he heard sporadic gunfire. He said that Palestinians were throwing rocks and that the Israeli forces “got scared and started shooting.” Matteer, bandaged, said that he was shot in the right arm and that the shrapnel will be removed later this week.

In the weeks since U.S. Secretary of State John F. Kerry persuaded Palestinian and Israeli negotiators to return to the table for talks, each side has accused the other of attempting to derail the process. The Palestinians are angered at announcements that thousands of new units will be built in Israeli settlements in the West Bank and East Jerusalem, while the Israelis have accused the Palestinians of inciting violence in their schools and textbooks.