Israel ramped up its criticism of the embattled UN agency for Palestinian refugees on Monday, saying 450 of its employees were members of militant groups in the Gaza Strip, although it provided no evidence to back up its accusation.

Major international funders have withheld hundreds of millions of dollars from the agency, known as UNRWA, since Israel accused 12 of its employees of participating in the October 7 Hamas attacks on Israel that killed 1,200 people and left 253 others held hostage in Gaza, according to Israeli authorities.

Philippe Lazzarini, the head of the agency known as UNRWA, told a press conference late on Monday that he “has never been informed” or received any evidence of Israel’s claims, and this is not the first.

Every year, he said, UNRWA provides Israel and the Palestinian Authority with a list of its staff “and I never have received the slightest concern about the staff that we have been employing.”

The only allegation communicated to him verbally was about 12 UNRWA staffers alleged to have participated in the October 7 attacks, he said, and they appeared so serious that they were fired, and two UN-ordered investigations are underway.

The UN envoy focusing on sexual violence in conflict, Pramila Patten, said on Monday there were “reasonable grounds” to believe Hamas committed rape, “sexualised torture” and other cruel and inhuman treatment of women during the attack.

The attack sparked an Israeli invasion of the enclave of 2.3 million people that Gaza’s Health Ministry says has killed more than 30,000 Palestinians. Aid groups say the fighting has displaced most of the territory’s population and sparked a humanitarian catastrophe.

UNRWA, which employs roughly 13,000 people in Gaza, is the biggest aid provider in the enclave.

The allegations on Monday were a significant escalation in the accusations against the agency. Rear Admiral Daniel Hagari, Israel’s chief military spokesperson, did not provide names or other evidence to back up the vastly increased number of UNRWA employees it said were militants.

“Over 450 UNRWA employees are military operatives in terror groups in Gaza – 450. This is no mere coincidence. This is systematic. There is no claiming, ‘we did not know,’” Hagari said.

UNRWA in a statement accused Israel of detaining several of its staffers and forcing them, using torture and ill treatment, into giving false confessions about the links between the agency, Hamas and the October 7 attack on Israel.

“These forced confessions as a result of torture are being used by the Israeli Authorities to further spread misinformation about the agency as part of attempts to dismantle UNRWA,” the statement said. “This is putting our staff in Gaza at risk and has serious implications on our operations in Gaza and around the region.’’

After Israel’s initial accusation against UNRWA, the agency fired the accused employees and more than a dozen countries suspended funding worth about $450 million, almost half its budget for the year.

Juliette Touma, director of communications for UNRWA, had no direct comment on the new Israeli allegations.

“UNRWA encourages any entity that has any information on the very serious allegations against UNRWA staff to share it with the ongoing UN investigation,” she said.

Two UN investigations into Israel’s allegations were already underway when the EU said on Friday it will pay €50 million ($54 million) to UNRWA after the agency agreed to allow EU-appointed experts to audit the way it screens staff to identify extremists.

Hagari also released a recording of a call he said was of an UNRWA teacher describing his role in the October 7 attack.

“We have female captives. I caught one,” the male voice is heard saying in Arabic. A man on a second call, alleged to be an Islamic Jihad militant who Israel also claimed was an UNRWA teacher, is heard saying “I’m inside with the Jews.”

The military named the men, although the man in the first call identified himself in the recording by a different name. The military said that name may have been a nickname. The military did not provide evidence as to their employment with UNRWA.

The accusations came as Benny Gantz, a top member of Israel’s wartime cabinet, met with US officials in Washington while talks were underway in Egypt to broker a cease-fire in Gaza before the Muslim holy month of Ramadhan begins next week.

Meanwhile, violence flared between Israel and Lebanon, amid inflamed tensions across the region.

An anti-tank missile fired into northern Israel from Lebanon killed a foreign worker and wounded seven others on Monday, Israel’s Magen David Adom rescue service said. The Hezbollah militant group in Lebanon did not immediately claim responsibility for Monday’s strike.

Hours later an Israeli airstrike in southern Lebanon killed three paramedics from Hezbollah’s health arm, Lebanon’s state media said. US envoy Amos Hochstein arrived in Beirut on Monday to meet with Lebanese officials in an attempt to tamp down tensions.

The near-daily clashes between Hezbollah and Israeli forces have killed more than 200 Hezbollah fighters and at least 37 civilians in Lebanon. Around 20 people have been killed on the Israeli side, including civilians and soldiers.

• An AP report