The U.N. agency for Palestinian refugees is asking Arab nations for funds after the Trump administration cut tens of millions of dollars of aid money.

UNRWA's chief, Pierre Krähenbühl, spoke to an Arab League meeting of foreign ministers Thursday in Cairo, saying the U.S. cut "is the most severe crisis" in the agency's history.

UNRWA, which serves some 5 million Palestinian refugees and their descendants, had a budget of over $1 billion last year, with the U.S. being the largest donor, giving a third of the total budget. The Trump administration withheld half of the first installment of payments this year, demanding reforms as a condition for future aid.

Last week, Krähenbühl suggested politics — notably the U.S. decision to recognize Jerusalem as the Israeli capital — were at play.