Israeli forces hit an aid warehouse in Rafah, the southernmost city in Gaza, on Wednesday, killing at least one staff member of the United Nations Relief and Works Agency and injuring 22 others, the agency said.

UNRWA is the largest aid group on the ground in Gaza and the chief lifeline for its 2.2 million residents, more than half of whom have been forced by Israeli military orders or fighting to cram into Rafah, at the enclave’s southernmost edge.

Philippe Lazzarini, the head of the agency, said in a statement that the “attack on one of the very few remaining UNRWA distribution centers in the Gaza Strip comes as food supplies are running out, hunger is widespread and, in some areas, turning into famine.”

The Israeli military did not immediately respond to a request for comment.

The UNRWA facility, in eastern Rafah, serves as both a warehouse for aid supplies and as a food distribution center. It was not distributing food to civilians on Wednesday, but more than 50 staff members were working at the facility when it was hit by Israeli forces around noon, said Juliette Touma, the agency’s director of communications.

Photos and video taken by Reuters photographers at the scene showed blood splashed in several locations around the facility: smeared on a warehouse floor surrounded by stacks of aid, soaked into the side of a box of medical supplies for babies and pooled on the ground outdoors.

At least 165 UNRWA staff members have been killed while working in Gaza since the start of the war, according to the agency. It also said that more than 400 people had been killed while sheltering at UNRWA facilities that had collectively been hit more than 150 times during the war.

Mr. Lazzarini said that UNRWA shared the coordinates of all of its facilities in Gaza on a daily basis with the “parties to the conflict,” and that the Israeli military had received the coordinates of the food distribution center on Tuesday, a day before it was hit.

“Attacks against U.N. facilities, convoys and personnel have become commonplace, in blatant disregard to international humanitarian law,” Mr. Lazzarini said.

Martin Griffiths, the top humanitarian chief at the United Nations, condemned the strike on the warehouse on social media, calling it “devastating” for both aid workers and “for the families they were trying to help.”

“They must be protected,” he said. “This war has to stop.”