The Israeli military said the two men had been killed during a “violent exchange” between Israeli settlers and Palestinians that followed a report of a Palestinian attacking an Israeli shepherd. An initial investigation indicated that the gunfire “did not originate” from Israeli soldiers, the military said.

The two Palestinians appeared to have been shot by Israeli settlers on the scene, said an Israeli security official, who spoke on the condition of anonymity because the investigation was still underway.

The killings fed fears that the West Bank could become another front for a country already in its seventh month of war in the Gaza Strip.

About 500,000 Israeli settlers in the West Bank live alongside roughly 2.7 million Palestinians under Israeli military occupation. Since the war began on Oct. 7, more than 400 Palestinians have been killed by Israeli forces there and in East Jerusalem, according to the United Nations.

Over the past few days, a renewed wave of violence has swept through the West Bank.

On Friday, a 14-year-old Israeli teenager went missing, prompting Israeli settlers to riot inside a Palestinian village, Al Mughayir. Jihad Abu Aliya, a 25-year-old resident, was fatally shot during a mob attack, according to the village mayor, Amin Abu Aliya.

The teenager, Binyamin Achimair, was found dead on Saturday after an intensive search; Israeli officials said he had been murdered in an act of terrorism and vowed to track down the perpetrators. In response, Israeli settlers, some of them armed, conducted a series of mob assaults in Palestinian towns, torching homes and cars, according to Palestinian witnesses.

Prime Minister Benjamin Netanyahu called on Israelis to allow security forces to search for Mr. Achimair’s killers, but he did not denounce the mob attacks against Palestinians. Human rights groups have long charged that Israel turns a blind eye to settler violence and rarely brings perpetrators to justice.

In footage distributed on Sunday by Yesh Din, an Israeli rights group that tracks Jewish extremist violence in the West Bank, hooded figures can be seen setting a car ablaze while Israeli soldiers watch nearby without intervening.

The United Nations human rights office said on Tuesday that Israeli security forces “must immediately end their active participation in and support for settler attacks on Palestinians.”

“Israeli authorities must instead prevent further attacks including by bringing those responsible to account,” said Ravina Shamdasani, a spokeswoman for the office. “Those reasonably suspected of criminal acts, including murder or other unlawful killings, must be brought to justice,” she added.

Matthew Miller, the State Department spokesman, condemned Mr. Achimair’s killing in a statement on Monday. But he also said Washington was “increasingly concerned by the violence against Palestinian civilians and their property that ensued in the West Bank after Achimair’s disappearance.”

“We strongly condemn these murders, and our thoughts are with their loved ones,” Mr. Miller said. “ The violence must stop. Civilians are never legitimate targets.”

Nick Cumming-Bruce contributed reporting.