The Israeli military suffered the deadliest day of its ground invasion of the Gaza Strip on Monday when 24 soldiers were killed, about 20 of them in an explosion as they were preparing to level buildings to help create a buffer zone with the Palestinian enclave, Israeli officials said.
The deaths plunged Israel into a state of mourning as Prime Minister Benjamin Netanyahu faces intensifying domestic divisions over how to proceed in the war as well as growing international condemnation of the civilian death toll in Gaza and the worsening humanitarian conditions there.
Israelis leaders expressed heartbreak over the deaths, but declared that the fighting would continue until Hamas was defeated. Mr. Netanyahu said that Israel had “experienced one of the most difficult days since the start of the war,” but that “we will not stop fighting until complete victory.”
The prime minister also said the military was investigating the events leading up to the blast that killed the soldiers, all of them reservists, near Gaza’s border with Israel. “We need to learn the necessary lessons and do everything to preserve our soldiers’ lives,” Mr. Netanyahu said in a statement on Tuesday.
With no end of the war in sight, and the United Nations reporting that more than half a million people in Gaza were facing “catastrophic hunger,” the Israeli military pressed ahead with its offensive. On Tuesday, it said it had encircled the largest city in southern Gaza, Khan Younis, in a major campaign marked by intense gun battles and bombardments in an area packed with civilians.
Many Gazans, seeking safety in Khan Younis, had fled their homes in other parts of the territory.
Philippe Lazzarini, the head of a U.N. Palestinian aid agency, said on Tuesday that one of its largest shelters in Khan Younis had been hit. At least six people were killed, he said, and many more were injured during heavy fighting around the shelter. Mr. Lazzarini did not say which side he believed responsible for the deaths and injuries. The Israel Defense Forces did not immediately respond to a request for comment on the U.N. report.
The Israeli military described the area where the fighting was taking place as a “significant stronghold” of Hamas’s Khan Younis brigade and said that it had killed dozens of Hamas fighters over the previous 24 hours. The military’s claims could not be independently verified.
In a statement, the military said its forces had targeted “terrorist cells” carrying rocket-propelled grenade launchers, as well as militants who had launched anti-tank missiles and had rigged buildings with explosives. “Ready-to-launch rockets, military compounds, shafts, and numerous weapons were located during the activity,” the statement said.
With Israeli tanks and troops surging into areas around the city’s hospitals, displaced civilians said they had no safe place to go.
Eman Jawad, who had sought safety in an industrial zone in Khan Younis, said that Israeli forces surrounded her shelter on Sunday night and that heavy clashes had broken out with Hamas fighters. The fighting was so close, she said, that several tents housing displaced people went up in flames.
“We are trapped,” Ms. Jawad said in a voice message on Monday. “There are snipers on the streets, and we are not allowed to leave the industrial zone.”
Rasha Ahmad, 31, said she wanted to leave Khan Younis and head to Rafah, Gaza’s southernmost district, but could not find a safe route. “Israeli tanks were everywhere,” she said. In the end, she said, she and many others decided to make the nearly four-hour trek on foot anyway.
“Five men were shot by a sniper in front of my eyes,” Ms. Ahmad said in one of a series of voice messages on Monday. “I’m sure they are dead — they were left to bleed on the ground.” The New York Times could not verify her account independently.
The Israeli solders who were killed in the blast on Monday died after Gazan militants fired on a tank guarding an Israeli unit that was setting explosives inside buildings, with the intention of demolishing them, the Israeli military said. During the firefight, the explosives detonated and two buildings collapsed, killing many of the soldiers inside, the military said.
Hamas’s military wing said that it had carried out an attack on a building in central Gaza on Monday, leading to an explosion that leveled it. It added that it had also hit a tank guarding the building and that it had detonated mines in the area.
Israel wants to demolish many of the Palestinian buildings close to the border to create a “security zone,” according to three Israeli officials, who spoke on the condition of anonymity because they were not authorized to discuss the operation. Two of the officials said that the goal was to create a buffer about a half-mile wide along the entire length of Israel’s roughly 36-mile border with Gaza.
Israel launched its offensive after Hamas-led militants crossed from Gaza into southern Israel on Oct. 7, killing a reported 1,200 people and taking 240 hostages. Since then, more than 25,000 people in Gaza have been killed, and the vast majority of residents have been forced from their homes into tents or shelters, according to the territory’s health officials.
Israeli officials said the buffer zone would make it harder for militants from Gaza to carry out another cross-border attack like the one in October.
After that rampage, tens of thousands of residents of southern Israel were evacuated, and Israeli leaders are hoping to persuade them that it is safe to return home. Some of the demolished areas in Gaza are a few hundred yards from Israeli neighborhoods that were attacked.
“The I.D.F. is operating in the area in order to prevent Hamas activity threatening the citizens of Israel,” the Israel Defense Forces said in a statement. “As part of this, the I.D.F. is locating and destroying terror infrastructures embedded, among other things, inside buildings.”
The military’s chief spokesman, Rear Adm. Daniel Hagari, told reporters on Tuesday that the soldiers who died had been involved in an operation to “create the security conditions for the return of the residents of the south to their homes.” He did not elaborate.
To Palestinians, the demolition along the border is a cruel practice that will prevent residents of the already crowded enclave from returning to their homes. Critics of Israeli policy in Gaza say it is part of a broader disregard for civilian housing and property.
Balakrishnan Rajagopal, the United Nations special rapporteur on the right to adequate housing, said a systematic demolition of Palestinian border homes could constitute a war crime because they pose no immediate threat to Israel.
“There is simply no provision in the Geneva Conventions for what Israel is doing along the border, which is kind of a pre-emptive clearing of property,” said Professor Rajagopal, an expert in law and development at the Massachusetts Institute of Technology.
“On a particular property-by-property basis, Israel can take action, but not on a widespread basis across the entire border,” Professor Rajagopal said. “Israel, as the occupying power, has an obligation not to engage in what’s called wanton destruction of property.”
The Israeli military did not respond to a request for comment on the claims.
The United States on Tuesday reiterated its opposition to any buffer zone inside Gaza. “We do not want to see the territory of Gaza reduced in any way,” John F. Kirby, a National Security Council spokesman, told reporters at the White House. Secretary of State Antony J. Blinken, speaking at a news conference in Abuja, Nigeria, added that the Biden administration might be open to “transitional arrangements.”
While Israel has never formally announced the demolition of Palestinian border homes, the concept of a buffer zone along the Gazan border has been widely discussed by the Israeli news media since early December, when the idea was reported by Reuters.
Israeli government ministers have also hinted at plans to create such a zone since the first weeks of the war. Eli Cohen, the foreign minister at the time, said that after the war, “the territory of Gaza will also decrease.”
Days later, Avi Dichter, the agriculture minister, spoke of creating “a margin” along the Gaza border. “No matter who you are, you will never be able to come close to the Israeli border,” Mr. Dichter said.
Patrick Kingsley and Ronen Bergman reported from Jerusalem, and Ameera Harouda from Doha, Qatar. Reporting was contributed by Michael Levenson, Matthew Mpoke Bigg, Gabby Sobelman, Rawan Sheikh Ahmad, Adam Rasgon, Victoria Kim, Johnatan Reiss, Hiba Yazbek, Anushka Patil , Erica L. Green and Michael Crowley.