Secretary-General Antonio Guterres on Friday pleaded for donors to fund the embattled UN agency for Palestinian refugees, warning there was no alternative despite Israeli criticism of the body.

At a pledging conference, Guterres warned that suffering Palestinians would lose a “critical lifeline” without the agency known as UNRWA.

“Let me be clear — there is no alternative to UNRWA,” he said.

“Just when we thought it couldn’t get any worse in Gaza — somehow, appallingly, civilians are being pushed into ever deeper circles of hell.”

Philippe Lazzarini, the chief of UNRWA, said the agency will be unable to function beyond August without receiving more funding.

A UN emergency appeal for $1.2 billion for the Palestinians by the end of the year, along with an appeal for neighboring countries, has received less than 20 percent of the funding it needs, Lazzarini said.