The United Nations chief is warning that a U.S.-induced half-billion-dollar funding shortfall for the U.N. relief agency for Palestinians risks cutting critical services that could "push the suffering in disastrous and unpredictable directions."

Secretary-General Antonio Guterres addressed an emergency funding conference in Rome on Thursday after the Trump administration slashed tens of millions to the U.N. Relief and Works Agency, the U.N.'s oldest and largest aid agency in the Middle East.

Guterres said investment in U.N. programs addresses the despair and other factors "that lead to radicalization."

The Trump administration announced in January it was slashing $65 million this year. But the U.N. said the actual cut was to the tune of $300 million because the U.S. had led the agency to believe it would provide $365 million in 2018.