Israeli Prime Minister Benjamin Netanyahu said Israel’s armed forces had “unintentionally” struck a convoy from the humanitarian group World Central Kitchen in Gaza late Monday, killing seven aid workers.

“Unfortunately, in the last day there was a tragic case of our forces unintentionally hitting innocent people in the Gaza Strip,” Netanyahu said Tuesday as he left a hospital in Jerusalem after a hernia operation. “It happens in war. We will investigate it right to the end. … We are in contact with the governments, and we will do everything so that this thing does not happen again.”

Earlier, the Israel Defense Forces expressed “sincere sorrow” over the deaths while stopping short of accepting responsibility.

In response to the killings, World Central Kitchen suspended its operations delivering vital food aid in Gaza, where Israel’s offensive has pushed hundreds of thousands of Palestinians to the brink of starvation. Cyprus, which has played a key role in trying to establish a maritime corridor, said ships were returning with some 240 tons of undelivered aid.

The strike killed the six World Central Kitchen aid workers and their Palestinian driver, the group said Tuesday, hours after it brought a new shipload of food into northern Gaza, which has been isolated and pushed near famine by Israel’s offensive.

The IDF said it was doing “an in-depth investigation of the incident by the most senior ranks, in order to understand all the circumstances of the incident. The IDF makes great efforts to enable the safe passage of humanitarian aid, and works in full cooperation and coordination with the WCK organization in order to support their efforts to provide food and humanitarian aid to the residents of the Gaza Strip.”

Graphic photographs showed the mangled, bloodied corpses of the aid workers, some still wearing World Central Kitchen t-shirts, with their passports, at Al-Aqsa Martyrs Hospital in the central Gaza town of Deir al-Balah.

A local resident told CBS News that the World Central Kitchen convoy was traveling from Deir al-Balah to Khan Younes at around midnight. The resident said they saw the rear vehicle in the convoy get hit first. The lead vehicle then stopped and went to the rear vehicle, where an injured passenger was pulled out. After that, the lead vehicle was hit, the witness said.

The food charity said early Tuesday that the seven killed included citizens of Australia, Poland and the United Kingdom, and that one was a U.S.-Canada dual citizen and one was Palestinian.

WCK, a nonprofit founded by celebrity chef José Andrés, has shipped more than 37 million meals to Palestinians in Gaza since Oct. 7, the group says.

“This is not only an attack against WCK, this is an attack on humanitarian organizations showing up in the most dire of situations where food is being used as a weapon of war. This is unforgivable,” World Central Kitchen CEO Erin Gore said in a statement

In a lengthy social media post, Andrés said his organization had lost several “brothers and sisters in an IDF air strike in Gaza,” and called on the Israeli government to “stop killing civilians and aid workers, and stop using food as a weapon.”

“I am heartbroken and grieving for their families and friends and our whole WCK family,” Andrés wrote. “These are people … angels … I served alongside in Ukraine, Gaza, Turkey, Morocco, Bahamas, Indonesia. They are not faceless … they are not nameless.”

IDF spokesperson Rear Admiral Daniel Hagari said in a statement that he’s spoken with Andrés and “expressed the deepest condolences of the Israel Defense Forces to the families and the entire World Central Kitchen family. We also express sincere sorrow to our allied nations who have been doing and continue to do so much to assist those in need.”  

The WCK team “was traveling in a deconflicted zone in two armored cars branded with the WCK logo,” the group said in a statement.

“Despite coordinating movements with the (Israeli army), the convoy was hit as it was leaving the Deir al-Balah warehouse,” in central Gaza, the group said, adding that the team had unloaded more than 100 tons of humanitarian food aid brought to Gaza on the maritime route.

In the face of a growing humanitarian disaster in Gaza’s north, several countries worked to open a sea route, hoping it would enable more aid to enter the territory, where supplies have only trickled in through the land routes controlled by Israel. The United States and other countries have also airdropped aid, but humanitarian workers say such efforts are far from sufficient to meet mounting needs.

Israel has barred UNRWA, the main U.N. aid group in the region, from making deliveries to the north, and other aid groups say sending truck convoys north has been too dangerous because of the military’s failure to ensure safe passage.

Three aid ships from the Mediterranean island nation of Cyprus arrived earlier Monday carrying some 400 tons of food and supplies organized by World Central Kitchen and the United Arab Emirates following a pilot was run last month. The Israeli military was involved in coordinating both deliveries.

Cypriot Foreign Ministry spokesman Theodoros Gotsis said Tuesday that around 100 tons of aid had been unloaded before the charity suspended operations, and that the remaining 240 tons of aid would be transported back to Cyprus.

The United States, which has provided key military and diplomatic support for Israel’s offensive, has touted the sea route as a new way to deliver desperately needed aid to northern Gaza, where the U.N. has said much of the population is on the brink of starvation, largely cut off from the rest of the territory by Israeli forces. The U.S. plans to build its own floating dock for aid delivery, with construction expected to take several weeks.

Israel has barred UNRWA, the main U.N. agency in Gaza, from making deliveries to the north, and other aid groups say sending truck convoys north has been too dangerous because of the military’s failure to ensure safe passage.

The UNRWA said in its latest report that 173 of its colleagues have been killed in Gaza in the violence. The figure does not include workers for other aid organizations.

Australian Prime Minister Anthony Albanese confirmed that Zomi Frankcom, 44, of Melbourne, was among those killed and said his government has requested an explanation from Israel.

“This is someone who was volunteering overseas to provide aid through this charity for people who are suffering tremendous deprivation in Gaza. And this is just completely unacceptable,” Albanese told reporters.

British Foreign Secretary David Cameron said his country was working to verify reports of the deaths of U.K. nationals in the strike, which he said was “deeply distressing.”

“It is essential that humanitarian workers are protected and able to carry out their work,” he wrote on X, also calling for an investigation.

Poland’s Foreign Ministry posted “sincerest words of sympathy” to the family of a volunteer who had offered assistance to Palestinians in the Gaza Strip, without saying how he was killed. The Foreign Ministry said it is requesting an explanation from Israel.

The mayor of Przemysl, Wojciech Bakun, named the victim on Facebook as Damian Soból and said he was from the city in southeastern Poland.

U.S. National Security Council spokesperson Adrienne Watson said on social media that, “We are heartbroken and deeply troubled by the strike that that killed [World Central Kitchen] aid workers in Gaza. Humanitarian aid workers must be protected as they deliver aid that is desperately needed, and we urge Israel to swiftly investigate what happened.”

WCK said the shipments bound for Gaza were loaded with rice, pasta, flour, legumes, canned vegetables and proteins, and contained enough food to prepare more than 1 million meals. Also on board were dates, which are traditionally eaten to break the daily fast during the holy month of Ramadan.

The United Nations and partners have warned that famine could occur very soon in devastated, largely isolated northern Gaza. CBS News previously reported that an estimated 1.7 million people in Gaza have been displaced in the territory, according to the U.N., with many having no access to food, water, medicine or appropriate shelter.

Tens of thousands of people, mostly civilians, have been killed since Oct. 7, when Hamas-led militants stormed into southern Israel, killing some 1,200 people and taking around 250 hostage. Israel responded with an air, land and sea offensive that has killed nearly 33,000 Palestinians, according to Gaza’s Health Ministry. The ministry doesn’t distinguish between civilians and combatants in its count, but it says women and children make up around two-thirds of those killed.

—S. Dev, Brian Dakss and Camilla Schick contributed reporting.