U.N. Secretary-General Antonio Guterres on Wednesday described the U.N. Palestinian refugee agency (UNRWA) as "the backbone of all humanitarian response in Gaza" and appealed to all countries to "guarantee the continuity of UNRWA's lifesaving work."

The United States is the biggest donor to the U.N. Relief and Works Agency for Palestine Refugees in the Near East and has temporarily paused its funding – along with several other countries – after Israel accused some agency staff of taking part in the Oct. 7 attack by Hamas militants, Reuters reports.

“I was personally horrified by these accusations,” Guterres told the U.N. Committee on the Exercise of the Inalienable Rights of the Palestinian People. “Yesterday, I met with donors to listen to their concerns and to outline the steps we are taking to address them.”

The accusations became public on Friday when UNRWA announced it had fired some staff after Israel provided the agency with information. Guterres said on Sunday that of 12 people implicated nine were fired, one is dead, and the identity of the remaining two was being clarified.

An Israeli intelligence dossier, seen by Reuters on Monday, includes accusations that some UNRWA staff took part in abductions and killings during the Oct. 7 raid that sparked the Gaza war and alleges some 190 UNRWA employees have doubled as Hamas or Islamic Jihad militants.

The Palestinians have accused Israel of falsifying information to tarnish UNRWA. UNRWA employs 13,000 people in Gaza, running schools, its primary healthcare clinics and other social services, and distributing humanitarian aid, Reuters says.

“The humanitarian system in Gaza is collapsing,” Guterres said. “I am extremely concerned by the inhumane conditions faced by Gaza’s 2.2 million people, as they struggle to survive without any of the basics.”