“We are aware of reports that members of the World Central Kitchen team have been killed in an IDF attack while working to support our humanitarian food delivery efforts in Gaza,” a spokesperson for the group said. “This is a tragedy. Humanitarian aid workers and civilians should never be a target.”

World Central Kitchen did not name those killed in its statement, though videos of a news conference held at al-Aqsa Martyrs Hospital on Monday appeared to show the passports of foreign nationals from Britain, Poland and Australia with the dead. One of those killed was identified as a Palestinian man, described in the news conference as the aid workers’ driver at the time of the strike. Some of the dead appeared to be wearing clothing featuring World Central Kitchen logos.

The Israel Defense Forces said the same day in a statement that it was aware of the reports and conducting “a thorough review at the highest levels to understand the circumstances of this tragic incident.”

The reported strike could mark the first time that foreign national aid workers have been killed in Gaza since the start of the war on Oct. 7, though a record number of Palestinians employed by the United Nations have been killed in the conflict.

“The Israeli government needs to stop this indiscriminate killing. It needs to stop restricting humanitarian aid, stop killing civilians and aid workers, and stop using food as a weapon,” Andrés wrote on social media.

Australian Prime Minister Anthony Albanese said Tuesday local time that the death of Lalzawmi Frankcom, known to her friends as Zomi, was “completely unacceptable.”

“We want full accountability for this, because this is a tragedy that should never have occurred,” Albanese said at a news conference, adding that Canberra had contacted the Israeli government and Israel’s ambassador to Australia.

“The truth is that this is beyond any reasonable circumstance — [that] someone going about providing aid and humanitarian assistance should lose their life,” he said.

In a post on social media, National Security Council spokeswoman Adrienne Watson urged Israel to investigate what happened. “Humanitarian aid workers must be protected as they deliver aid that is desperately needed,” she wrote.

Israel is facing increasing pressure from the United States and other Western allies over the humanitarian toll of the war, as well as looming issues of international humanitarian law. In an order last week, the International Court of Justice called on Israel to “take all necessary and effective measures” to ensure the provision of basic services and humanitarian assistance to Palestinians in the enclave.

“I served alongside [them] in Ukraine, Gaza, Turkey, Morocco, Bahamas, Indonesia,” Andrés wrote of those killed on Monday. “They are not faceless…they are not nameless.”

“If they are aid workers, they are civilians, and civilians are protected from attack under the law of war,” said Brian Finucane, a former legal adviser at the State Department and now a senior adviser at Crisis Group.

Speaking at the news conference Monday, Ismail al-Thawabta, the head of the government media office in Gaza, said it was “time for everyone to come out and denounce the massacres that took place today, affecting four foreign nationals working in the Gaza Strip.”

The Spanish-born Andrés formed World Central Kitchen in 2010. It quickly grew into a high-profile relief organization for natural disasters and war zones, as Andrés used his status to raise awareness of crises in places such as Ukraine and Haiti.

In Gaza, the organization most notably led the construction of a jetty that allowed a ship chartered by the Spanish search-and-rescue group Open Arms to send about 200 tons of food and water to the enclave.

Israel declared a full-scale siege of Gaza in a bid to oust the militant group Hamas, which was behind the Oct. 7 attacks on Israel. Global emergency experts have warned that up to half of the Gaza Strip’s population will face starvation before July.

In a statement last month, World Central Kitchen said it had served more than 35 million meals since the war began and opened more than 60 community kitchens across Gaza.

Andrés had personally lobbied the Israeli government to allow more food into Gaza, according to a Wall Street Journal report. In its statement Monday, the IDF said it had been working with World Central Kitchen to help the organization’s efforts.

“The IDF makes extensive efforts to enable the safe delivery of humanitarian aid, and has been working closely with [World Central Kitchen] in their vital efforts to provide food and humanitarian aid to the people of Gaza,” the IDF said in the statement.

Michael Miller in Sydney and Kelsey Ables in Seoul contributed to this report.