A top official says the U.N. aid agency for Palestinian refugees faces the worst financial crisis in its 65-year history, coming up short hundreds of millions of dollars in 2015, including for emergency operations in war-ravaged Gaza and Syria.

Pierre Kraehenbuehl, commissioner of the U.N. Relief and Works Agency, also said Monday that the "growing denial of dignity and of rights of Palestine refugees, their increasing needs and increasing hopelessness ... represent a time bomb in the region."

He says "political failure" by the international community and others allowed the refugee problem to fester for so long.

The agency cares for Palestinians displaced in Mideast wars since Israel's 1948 creation. Today, some 5 million refugees and their descendants live in the West Bank, Gaza and neighboring Arab countries.