In a statement, Lazzarini called the allegations “shocking” and said any employee “involved in acts of terror will be held accountable, including through criminal prosecution.”

He did not elaborate on what the staffers’ alleged role was in the attacks. In the unprecedented surprise attack, Hamas fighters broke through the security fence surrounding Gaza and stormed nearby Israeli communities, killing around 1,200 people, mostly civilians, and kidnapping some 250. Other militants joined the rampage.

“UNRWA reiterates its condemnation in the strongest possible terms of the abhorrent attacks of 7 October” and calls for the immediate and unconditional release of all Israeli hostages, Lazzarini said.

Since the war’s start, Israel’s assault has killed more than 26,000 Palestinians, most women and children, and wounded more than 64,400 others, Gaza’s Health Ministry said Friday. The ministry does not differentiate between combatants and civilians in its death toll. More than 150 UNWRA employees are among those killed — the highest toll the world body has suffered in a conflict — and a number of U.N. shelters have been hit in the bombardment.

More than 1.7 million of Gaza’s 2.3 million people have been driven from their homes by the war — with hundreds of thousands of them crowded into schools and other shelters run by UNRWA.

Israel’s near-complete seal on Gaza has left almost the entire population reliant on a trickle of international aid able to enter the territory each day. U.N. officials say about a quarter of the population now faces starvation.

The U.S. State Department said it was “extremely troubled” by the allegations against the UNRWA staffers and has temporarily paused additional funding for the agency. The U.S. is the biggest donor to the agency, providing it with $340 million in 2022 and several hundred million in 2023.

Stéphane Dujarric, spokesperson of U.N. Secretary-General António Guterres, said an “urgent and comprehensive” independent review of the agency would be conducted.

UNRWA was created to care for millions of Palestinians across the Middle East whose families fled or were forced from properties inside what is now Israel during the war surrounding Israel’s creation in 1948. Israel rejects a return of the refugees to their former lands.

Israeli officials and their allies — including in the U.S. Congress — frequently allege that UNRWA allows anti-Israeli incitement to be taught in its hundreds of schools and that some of its staff collaborate with Hamas. The Trump administration suspended funding to the agency in 2018, but President Joe Biden restored it.

The agency’s supporters say the allegations aim to diminish the long-festering refugee issue. Last week, Lazzarini said he would appoint an independent entity to look into the claims — both “what is true or untrue” and “what is politically motivated.” He also said the accusations were hurting the agency’s already stretched operations.

Thousands of Palestinians fled the southern Gaza city of Khan Younis on Friday as fighting between Hamas militants and Israeli forces intensified. Families were seen traveling on foot down roads, carrying possessions as smoke filed the skies above them.

Also Friday, the Israeli military ordered residents of three Khan Younis neighborhoods and the refugee camp in the city to evacuate to a coastal area. The military said its troops were engaging in close urban combat with Hamas fighters around the city.

The Khan Younis camp, like others in Gaza, was initially settled by Palestinians who fled or were driven from their homes during the 1948 war surrounding Israel’s creation and has since been built up into an urbanized district. The leader of Hamas in Gaza, Yehya Sinwar, and the commander of the group’s military wing, Mohammed Deif, both grew up in the Khan Younis refugee camp.

In central Gaza, the other main focus of Israel’s offensive currently, Israeli airstrikes on the Nuseirat urban refugee camp overnight killed at least 15 people, including a 5-month-old baby, said a journalist with The Associated Press at the hospital where the casualties were taken.

The intense fighting came as the United Nations’ top court ordered Israel to do all it can to prevent death, destruction and any acts of genocide in Gaza. But the International Court of Justice stopped short Friday of ordering it to end the military offensive. South Africa has accused Israel of genocide in its offensive, and the court dismissed a request by Israel, which rejects the accusation, that the case be thrown out.

Aid groups have struggled to bring food, medicines and other supplies to northern Gaza, where Israel’s ground invasion first targeted and where Israel says it now largely has control.

Uday Samir, a 23-year old Gaza City native, said many of the basic foods such as flour, lentils and rice are now impossible to find across the city.

“Now, what is available is animal feed,” said Samir. “We grind it and bake it.”

All supplies enter Gaza in the south, either through the Egyptian-controlled Rafah border crossing or Israel’s Kerem Shalom crossing. Aid groups say fighting and Israeli restrictions have made deliveries to the north difficult. When convoys do travel north, supplies are often snatched by hungry Palestinian before the trucks reach their destination.