Israel's foreign minister called Saturday for the head of the UN agency for Palestinian refugees to quit, following Israeli claims that a Hamas tunnel had been discovered under its evacuated Gaza City headquarters.

This picture taken during a media tour organised by the Israeli army on February 8 shows Israeli soldiers checking a shaft inside the evacuated Gaza City headquarters compound of the United Nations agency for Palestinian refugees.

Israel Katz dismissed UNRWA commissioner general Philippe Lazzarini's claim that he was unaware of its presence as "not only absurd but also an affront to common sense".

"His prompt resignation is imperative," he wrote on X, formerly Twitter.

Lazzarini, already under pressure after Israel claimed some UNRWA staff were involved in the October 7 Hamas attack, said the agency had not operated from the compound since October 12.

Instead he called for an independent investigation.

Hamas has previously denied Israeli claims that it has dug an extensive network of tunnels under schools, hospitals and other civilian infrastructure as cover for its activities.

Israel's army and the Shin Bet security agency said operations in Gaza City in recent weeks had led to the discovery of a "tunnel shaft" near a school run by the humanitarian agency.

"The shaft led to an underground terror tunnel that served as a significant asset of Hamas's military intelligence and passed under the building that serves as UNRWA's main headquarters in the Gaza Strip," they added in a statement.

"Electrical infrastructure" in the tunnel -- 700 metres (765 yards) long and 18 metres underground -- "connected" to the agency's HQ, "indicating that UNRWA's facilities supplied the tunnel with electricity", they said.

Documents and a stash of weapons in the UN compound itself "confirmed that the offices had in fact also been used by Hamas terrorists", the joint statement said.

Katz claimed the discovery showed UNRWA's "deep involvement" with Hamas.

- 'Inviolable' -

An AFP photographer was among a number of journalists taken to the compound and tunnel by the Israeli military on Thursday.

UN premises are considered "inviolable" in international law and immune from "search, requisition, confiscation, expropriation and any other form of interference".

Lazzarini wrote on X that its staff were forced to leave its Gaza City compound under instruction from Israeli forces as bombardment intensified in the area and had not returned.

"We have not used that compound since we left it nor are we aware of any activity that may have taken place there," he added.

The compound was last inspected in September 2023, he said.

Any suspicious "cavity" found near or under any UNRWA premises was previously reported to the authorities in Hamas-controlled Gaza and the Israelis, and also made public, he said.

The latest claims "merit an independent inquiry that is currently not possible to undertake given Gaza is an active war zone", he added.

"The Israeli authorities have not informed UNRWA officially about the alleged tunnel." Instead the agency learned about it from media reports, he said.

The UN has launched two separate probes into UNRWA, the first into Israeli claims that 12 of its staff may have participated on October 7, and the other a review of its overall political neutrality.

UN chief Antonio Guterres has spoken out in defence of the agency, calling it the "backbone" of Gaza aid.

So too has US Secretary of State Antony Blinken, who said it played an "absolutely indispensable role in trying to make sure that men, women and children who so desperately need assistance in Gaza actually get it."

Israel unveils tunnels underneath Gaza City headquarters of UN agency for Palestinian refugees

The Israeli military says it has discovered tunnels underneath the main headquarters of the U.N. agency for Palestinian refugees in Gaza City, alleging that Hamas militants used the space as an electrical supply room.

The unveiling of the tunnels marked the latest chapter in Israel's campaign against the embattled agency, which it accuses of collaborating with Hamas.

Recent Israeli allegations that a dozen staff members participated in the Hamas attack on Israel Oct. 7 plunged the agency into a financial crisis, prompting major donor states to suspend their funding as well as twin investigations. The agency says that Israel has also frozen its bank account, embargoed aid shipments and canceled its tax benefits.

The army invited journalists to view the tunnel on Thursday.

It did not prove definitively that Hamas militants operated in the tunnels underneath the UNRWA facility, but it did show that at least a portion of the tunnel ran underneath the facility's courtyard. The military claimed that the headquarters supplied the tunnels with electricity.

UNRWA Commissioner-General Philippe Lazzarini said the agency had no knowledge of the facility's underground, but the findings merit an “independent inquiry,” which the agency is unable to perform due to the ongoing war.

The headquarters, on the western edge of Gaza City, are now completely decimated. To locate the tunnel, forces repeated an Israeli tactic used elsewhere in the strip, overturning mounds of red earth to produce a crater-like hole giving way to a small tunnel entrance. The unearthed shaft led to an underground passageway that an Associated Press journalist estimated stretched for at least half a kilometer (quarter of a mile), with at least 10 doors.

At one point, journalists were able to gaze upward from the tunnel, through a hole, and make eye contact with soldiers standing in a courtyard within the UNRWA facility.

Inside one of the UNRWA buildings, journalists saw a room full of computers with wires stretching down into the ground. Soldiers then showed them a room in the underground tunnel where they claimed the wires connected.

That underground room bore a wall of electrical cabinets with multicolored buttons and was lined with dozens of cables. The military claimed the room served as a hub powering tunnel infrastructure in the area.

“Twenty meters above us is the UNRWA headquarters," said Lt. Col. Ido, whose last name was redacted by the military. "This is the electricity room, you can see all around here. The batteries, the electricity on walls, everything is conducted from here, all the energy for the tunnels which you walked though them are powered from here.”

The Associated Press journalist could see the tunnel stretching beyond the area underneath the facility.

Hamas has acknowledged building hundreds of kilometers (miles) of tunnels across Gaza. One of the main objectives of the Israeli offensive has been to destroy that network, which it says is used by Hamas to move fighters, weapons and supplies throughout the territory. It accuses Hamas of using civilians as human shields and has exposed many tunnels running near mosques, schools and U.N. facilities.

Lazzarini said the agency was unaware what lay beneath it, saying he had visited the facility multiple times and did not recognize the electrical room. In a statement, Lazzarini wrote that UNRWA had conducted a regular quarterly inspection of the facility in September.

“UNRWA is a human development and humanitarian organization that does not have the military and security expertise nor the capacity to undertake military inspections of what is or might be under its premises,” read the statement.

Also in the tunnel, journalists saw a small bathroom with a toilet and a faucet, a room with shelves and a room with two small vehicles in it that soldiers said the militants used to traverse the tunnel network. The military said Saturday night that the tunnel began at a UNRWA school, and was 700 meters (765 yards) long and 18 meters (20 yards) deep.

The military said forces uncovered rifles, ammunition, grenades, and explosives in the facility, claiming it has been used by Hamas militants. Lazzarini said the agency has not revisited the headquarters since staff evacuated Oct. 12, and is unaware of how the facility may have been used.

Israel has found similar primitive quarters in tunnels across Gaza over the course of its 4 month-long campaign in Gaza. The offensive was launched after Hamas militants attacked Israel on Oct. 7, killing some 1,200 people and dragging 250 hostages back to Gaza. Since then, Israeli war planes and ground troops have killed over 27,000 Palestinians in the strip, unleashed a humanitarian catastrophe and wreaked widespread damage.

Leaving the facility, it was nearly impossible to identify one window left fully intact. Bullet holes pockmarked the walls. Shrapnel was everywhere, crumpled-up U.N. vehicles were perched precariously atop building debris. Dogs roamed the area.

“The Israeli army is occupying our biggest UNRWA headquarters," Touma said in response to Israeli allegations. “That’s what’s outrageous.”

Biden and Netanyahu discuss hostage release at length during call Sunday, but gaps remain

President Joe Biden and Israeli Prime Minister Benjamin Netanyahu discussed a deal to secure the release of hostages in Gaza at length on Sunday, according to a senior administration official, who cautioned that while a framework is in place, gaps remain.

In their first call since January 19, Biden and Netanyahu discussed Israel’s ongoing campaign in Gaza, the return of hostages held by Hamas, and Israel’s anticipated ground assault on the city of Rafah, which has drawn concern from the US and from others in the region.

“The President reaffirmed our shared goal to see Hamas defeated and to ensure the long-term security of Israel and its people. The President and the Prime Minister discussed ongoing efforts to secure the release of all remaining hostages held by Hamas,” a statement from the White House said.

Over the last several months, the US has attempted to put more pressure on the Israeli government to support a “humanitarian pause” in its war against Hamas. But those efforts have yielded little success.

Last week, Netanyahu called Hamas’ recent proposals for a ceasefire and hostage deal in Gaza “delusional.”

The full Hamas response proposes three phases, each lasting 45 days, including the withdrawal of Israeli troops from Gaza, a massive humanitarian effort, and freedom of movement for people throughout Gaza, according to a copy obtained by CNN.

“There is not a commitment – there has to be a negotiation, it’s a process, and at the moment, from what I see from Hamas, it’s not happening,” Netanyahu said.

There are 136 hostages being held in Gaza, including 132 who were captured during Hamas’ October 7 attack. Twenty-nine of the hostages are dead, according to the Israeli prime minister’s office. Secretary of State Antony Blinken previously said negotiations toward an agreement would continue despite the Israeli prime minister’s comments, which Blinken said were referencing the “absolute non-starters” in the proposal.

The call between Biden and Netanyahu lasted about 45 minutes, and two-thirds of the call was focused on the release of hostages, according to the senior Biden administration official.

“There are certainly gaps that need to be closed. Some of them are significant, but there has been real progress over the last few weeks, and we are now seeking to do all we possibly can to capitalize on it,” the official said.

Biden on Sunday “reaffirmed his view that a military operation in Rafah should not proceed without a credible and executable plan for ensuring the safety of and support for the more than one million people sheltering there,” the White House said.

Netanyahu last week said the Israel Defense Forces would “soon go into Rafah, Hamas’ last bastion.” More than 1.3 million people are believed to be in the southern city, the majority of whom were displaced from other parts of Gaza, according to the United Nations.

Netanyahu called for the people in Rafah to evacuate ahead of the ground assault, but it is unclear where they could go; the city borders Egypt to the south, but the border has been closed for months. The US has said it would not support an Israeli military operation in Rafah “without serious planning” given the risks.

“We have made very clear that an operation under current conditions is not something that we could envision,” the senior administration official said.

Biden’s phone call with Netanyahu comes a few days after the president offered one of his sharpest rebukes to date of Israel’s military conduct in Gaza, saying the operation to go after Hamas had been “over the top.”

“I’m of the view, as you know, that the conduct of the response in Gaza – in the Gaza Strip – has been over the top,” Biden told reporters at the White House on Thursday, describing his own efforts to open up Gaza so more humanitarian aid could flow in.

Biden and Netanyahu didn’t specifically address the president’s comment, the senior administration official said.

Last week, Blinken told Netanyahu and other top Israeli officials that the civilian toll in Gaza “remains too high” as violence continues in the region.

“Nearly 2 million people have been displaced from their homes. Hundreds of thousands are experiencing acute hunger. Most have lost someone that they love. And day after day, more people are killed,” Blinken said at a news conference after meeting with top Israeli officials.

The Israeli offensive, launched after the Hamas attack just over four months ago, has taken an immense humanitarian toll on the strip, with tens of thousands dead and the population of Gaza on the brink of famine. Officials see a cessation in fighting as central to both their short- and longer-term objectives for Gaza as international and domestic US pressure to end the conflict mounts.

Earlier Sunday, Biden also spoke with Blinken, CIA Director Bill Burns, Vice President Kamala Harris, national security adviser Jake Sullivan and his senior White House team.