Nearly all of the agency’s funding comes from donations from countries including the United States, Germany and the European Union, but it has been struggling financially for years.

UNRWA entered 2023 with $75 million in debt and asked donors for $1.6 billion for its yearly budget, Ms. Touma said. But it had received less than half of that when the war began. Now, it has asked for an additional $481 million, mostly for Gaza.

As the war rages, most of the agency’s services are on hold as it focuses on providing emergency aid. More than half of Gaza’s population has been displaced because of Israel’s air campaign, and Israel has imposed a tight blockade, vowing not to let food, water or fuel into the territory. In recent weeks, only a trickle of aid trucks have entered Gaza via its border with Egypt.

The agency’s schools are shuttered and many of them are now among the more than 150 UNRWA facilities providing shelter for 730,000 people, the agency says.

Instead of running 14 food distribution centers, the agency is providing flour and fuel to bakeries, where Gazans often wait in line for hours to get bread.

The killings and displacement of UNRWA staff members and its inability to replenish its supplies have vastly limited its work, Ms. Touma said.

“We have seen in this war that food, water and fuel are being used as weapons of war,” she said.

It is too early to tell how the war will conclude and who will end up administering Gaza. Secretary of State Antony J. Blinken has suggested that the territory could eventually be reunited with the Israeli-occupied West Bank and governed by the Palestinian Authority, the internationally recognized representative of the Palestinians.

But on Saturday, Prime Minister Benjamin Netanyahu of Israel said his country must retain security control over Gaza “for as long as necessary” and dismissed the possibility of a role there for the Palestinian Authority.

Until a longer-term arrangement is made, UNRWA will likely remain the best placed organization to care for the population, experts say, although its battering by the war could leave it ill-equipped to do so.

“The scale of this is really unlike anything we have seen,” said Anne Irfan, a lecturer at University College London and the author of a recent book about UNRWA, referring to the Israeli bombardment of Gaza. “It is really difficult to see where we go from here, unless there are going to be really serious resources channeled into UNRWA.”