An Israeli airstrike killed at least 90 Palestinians in a designated humanitarian zone in Gaza on Saturday, the enclave’s health ministry said, in an attack that Israel said targeted Hamas military chief Mohammed Deif.

Israeli Prime Minister Benjamin Netanyahu said it remained unclear whether Deif and another Hamas commander had been killed and promised to continue to target Hamas leadership, saying more military pressure on the group would improve chances of a hostage deal, even as three days of ceasefire talks separately halted on Saturday.

“Either way, we will get to the whole of the leadership of Hamas,” Netanyahu told a news conference.

Hamas denied Deif had been killed, according to a senior Hamas official on Al Jazeera TV. Hamas earlier said Israeli claims it had targeted leaders of the group were false and aimed at justifying the attack, which was the deadliest Israeli attack in Gaza in weeks.

Displaced people sheltering in the area said their tents were torn down by the force of the strike, describing bodies and body parts strewn on the ground.

“I couldn’t even tell where I was or what was happening,” said Sheikh Youssef, a resident of Gaza City who is currently displaced in the Al-Mawasi area.

“I left the tent and looked around, all the tents were knocked down, body parts, bodies everywhere, elderly women thrown on the floor, young children in pieces,” he told Reuters.

United Nations chief Antonio Guterres, in a statement, said he was “shocked and saddened” by the civilian deaths, which underscored “nowhere is safe in Gaza,” and said international humanitarian law must be upheld.

The Israeli military said the strike against Deif also targeted Rafa Salama, the commander of Hamas’ Khan Younis Brigade, describing them as two of the masterminds of the Oct. 7 attack on southern Israel that triggered the nine-month war in Gaza.

Deif has survived seven Israeli assassination attempts, the most recent in 2021, and has topped Israel’s most wanted list for decades, held responsible for the deaths of dozens of Israelis in suicide bombings.

The Gaza health ministry said at least 91 Palestinians were killed in the strike and 300 injured, the deadliest toll in weeks in the conflict-shattered enclave.

Al-Mawasi is a designated humanitarian area that the Israeli army has repeatedly urged Palestinians to head to after issuing evacuation orders from other areas.

Reuters footage showed ambulances racing towards the area amidst clouds of smoke and dust. Displaced people, including women and children, were fleeing in panic, some holding belongings in their hands.

The Israeli military published an aerial photo of the site, which Reuters was not immediately able to verify, where it said “terrorists hid among civilians”.

“The location of the strike was an open area surrounded by trees, several buildings, and sheds,” it said in a statement.

The Israeli military official said the area was not a tent complex, but an operational compound run by Hamas and that several more militants were there, guarding Deif.

U.S. Defense Secretary Lloyd Austin spoke with Israeli Defence Minister Yoav Gallant on Saturday to discuss Israel’s Gaza operations and emphasized the need to minimise civilian harm, the Pentagon said.

Josep Borrell Fontelles, the European Union’s Foreign Affairs and Security Policy representative, called for an independent probe and condemned any potential violation of international law, posting on social media site X that the “end can’t justify all means.”

Hospital ‘full of patients’

Many of those wounded in the strike, including women and children, were taken to the nearby Nasser Hospital, which hospital officials said had been overwhelmed and was “no longer able to function” due to the intensity of the Israeli offensive and an acute shortage of medical supplies.

“The hospital is full of patients, it’s full of wounded, we can’t find beds for people,” said Atef al-Hout, director of the hospital, adding that it was the only one still operating in southern Gaza.

Gallant was holding special consultations, his office said, in light of “developments in Gaza”.

At ceasefire talks underway in Doha and Cairo, two Egyptian security sources, who spoke to Reuters on condition of anonymity, said negotiations had been halted after three days of intense talks. They cited the behaviour of Israeli mediators as revealing “internal discord”.

Ismail Haniyeh, the leader of Hamas, in a statement said the group had been in contact with mediators in Egypt and Qatar as well as Turkey and Oman, and cited the attacks on Saturday, calling for an ed to “these massacres against our people”.

Netanyahu, in his televised remarks Saturday evening, said he had not moved away from the framework presented by U.S. President Joe Biden.

A spokesperson for the White House National Security Council said Israel told U.S. officials it had targeted senior Hamas officials and that the Biden administration was seeking to learn more about the reported civilian casualties.

As the prime minister spoke, protesters continued to rally in Tel Aviv, singing songs and waving signs calling for the release of Israeli hostages in Gaza. Thousands of protesters also marched outside Jerusalem earlier in the day.

“Maybe it’s good, maybe it’s not good. I don’t know about Mohammed Deif, I know that keeping the war is bad for all of us,” said Ayala Metzger, the daughter-in-law of an Israeli hostage who took part in the hostage solidarity march near Jerusalem.

Also on Saturday, at least 20 Palestinians were killed in an Israeli attack on a prayer hall at a Gaza camp for displaced people in west Gaza City, Palestinian health and civil emergency officials said.

Critics have accused Israel of committing genocide against Palestinians, which Israel denies. It characterises its actions as self-defense to prevent another attack like the one on Oct. 7, though the International Court of Justice ordered Israel in January to take action to prevent acts of genocide.

Hamas-led militants killed 1,200 people and took more than 250 hostages in the cross-border raid into southern Israel on Oct. 7, according to Israeli tallies.

Israel has retaliated with its military action in Gaza that has killed more than 38,000 Palestinians, medical authorities in Gaza say.