Israel on Tuesday reported the deaths of 24 of its soldiers in the Gaza Strip, one of the single worst days for the Israeli military since launching its campaign to eliminate the Hamas militant group.

Israeli military spokesman Rear Admiral Daniel Hagari told reporters 21 of the soldiers were preparing to demolish two buildings with explosives Monday when a militant fired a rocket at a tank nearby and the explosives in the buildings went off, collapsing the structures onto the Israeli soldiers. Three other Israeli troops died in a separate attack.

Israeli Prime Minister Benjamin Netanyahu said the military opened “an inquiry into the tragedy.”

“Yesterday we experienced one of our most difficult days since the war erupted,” Netanyahu said. “In the name of our heroes, for the sake of our lives, we will not stop fighting until absolute victory.”

Israeli Defense Minister Yoav Gallant wrote early Tuesday on X, formerly Twitter, that it was a “difficult and painful morning.”

“This war will determine the future of Israel for decades to come, and the fall of soldiers is a requirement to achieve the goals of the war,” Gallant said.

Israeli forces carried out intense bombing in southern Gaza, while health officials accused Israel of attacking health facilities.

The Palestinian Red Crescent said Israeli shelling struck the group’s headquarters in Khan Younis, “coinciding with intense gunfire from Israeli drones, resulting in injuries among internally displaced individuals who sought safety on our premises.”

Reuters reported Gaza health ministry spokesman Ashraf al Qidra telling the news agency that Israeli forces stormed a hospital and arrested medical staff in Khan Younis.

Israel did not immediately comment on the situation, but in the past the Israeli military has accused Hamas of operating in and around hospitals, which Hamas denies.

The United States on Monday called for Israel to protect civilians in hospitals.

White House National Security Council spokesperson John Kirby said that while Israel has a right to defend itself, “We expect them to do so in accordance with international law and to protect innocent people in hospitals, medical staff and patients as well, as much as possible.”

Israel vowed to destroy Hamas, which governs Gaza, after the militant group sent fighters rampaging into Israel on Oct. 7, killing around 1,200 people, mostly civilians, according to Israeli tallies. Hamas, which has been designated a terrorist organization by the United States, the United Kingdom, the European Union and others, also took about 240 people hostage.

The Hamas-run Health Ministry in Gaza says at least 25,295 Palestinians have been killed in the war, many of them women and children. The ministry does not specify the number of civilians and Hamas fighters among the dead.

The war has been devastating for Palestinian civilians, with the United Nations saying 85% of the population has been forced from their homes and a quarter of the people are facing starvation.

Some information for this report was provided by The Associated Press, Agence France-Presse and Reuters.