"Let me be clear: There is simply no alternative to UNRWA," WHO Director-General Tedros Ghebreyesus said in a video posted on X.

"This ban will not make Israel safer. It will only deepen the suffering of the people of Gaza and increase the risk of disease outbreaks," he added.

His comments came after Israel said it had formally notified the UN of its decision to sever ties with UNRWA after Israeli lawmakers backed the move last week.

The agency’s suspension sparked global condemnation, including from a key Israeli backer, the United States.

UNRWA supports Palestinian refugees with humanitarian aid in Gaza, the occupied West Bank, and East Jerusalem, as well as surrounding countries.

The move is expected to come into force in late January, with the UN Security Council warning it would have severe consequences for millions of Palestinians.

Israel has accused a dozen UNRWA employees of taking part in the 7 October 2023 attack by Hamas, the deadliest in Israeli history.

A series of probes found some "neutrality-related issues" at UNRWA. Still, they said Israel had not provided evidence for its allegations.

The agency, which employs 13,000 people in Gaza, fired nine employees after an internal probe found that they "may have been involved in the armed attacks of 7 October."

UNRWA, which was established in 1949 after the first Arab-Israeli war following Israel's creation a year earlier, assists nearly six million Palestinian refugees across Gaza, the West Bank, Lebanon, Jordan, and Syria.

"Every day, it provides thousands of medical consultations and vaccinates hundreds of children," Ghebreyesus said, adding that many humanitarian partners rely on UNRWA's logistical networks to get supplies into Gaza.

He said that the UNRWA staff his organization had worked with were "dedicated health and humanitarian professionals who work tirelessly for their communities under unimaginable circumstances."

The Israeli genocidal war against Gaza has killed at least 43,374 people, most of them women and children, with more than 102,261 others injured since 7 October 2023.

Juliette Touma, UNRWA director of communications, said UNRWA received one formal accusation directly from Israeli authorities, alleging 100 staff were associated with Palestinian armed groups. Touma said Israel has not responded to their requests for evidence.

Israel told the United Nations it was cancelling the agreement that regulated its relations with the UNRWA because Hamas was operating within the organization.