Lalzawmi Frankcom’s text message was short and sweet: a heart emoji reply at 10:38 p.m. on Sunday to her friend Josh Phelps, who had sent along photos of their humanitarian work together on a reservation in South Dakota.

Ms. Frankcom, an Australian known as Zomi, had a big day ahead on Monday. She and her colleagues from World Central Kitchen in Gaza were waiting for a ship to arrive at their newly built jetty so that they could unload hundreds of tons of sorely needed humanitarian aid.

The team set off about 8 a.m. on Monday local time from Rafah, in southern Gaza, and headed north to Deir al Balah. They “were so excited, like they were going to a wedding,” said Shadi Abu Taha, whose brother, Saif, was among them.

But the trip ended disastrously.

Israeli strikes hit their convoy that night, killing Ms. Frankcom and six of her colleagues from World Central Kitchen, the charity group founded by the chef José Andrés that has been delivering millions of meals in Gaza.

Many countries, including Australia, Britain and the United States, where some of the workers were from, have condemned the attack and called for investigations and accountability.

Israel’s prime minister, Benjamin Netanyahu, who has almost unequivocally rejected international criticism over his nation’s prosecution of the war against Hamas, said on Tuesday night that Israel “deeply regrets the tragic incident.”

Israel’s military said the strikes had resulted from a “misidentification,” but has not offered further details. “It was a mistake that followed a misidentification, at night during the war in a very complex condition,” the Israeli military’s chief of staff, Lt. Gen. Herzi Halevi, said in a video on Tuesday. “It shouldn’t have happened.”

The deaths pushed the number of aid workers killed during the war in Gaza to at least 196, including more than 175 United Nations employees, many of them local Palestinians, according to the U.N. secretary general, António Guterres, who called the death toll “unconscionable.”

The deadly Israeli strike is also setting back attempts to address the hunger crisis in the Gaza Strip, with aid groups saying they are now being more cautious about making deliveries and at least two suspending operations. World Central Kitchen itself stopped its work in Gaza and sent three ships with hundreds of tons of food back to port in Cyprus.

The World Central Kitchen’s ship, the Jennifer, had arrived in Gaza on Monday morning. It was carrying about 332 tons of aid that it would unload at the rudimentary jetty, which had been built in six days from the rubble of bombed buildings.

The workers spent the day getting 100 tons of supplies off the vessel and to their warehouse a few miles south in Deir al Balah. They also had a meeting with the U.N.’s senior humanitarian and reconstruction coordinator for Gaza, Sigrid Kaag.

The rest of the unloading would have to wait until the next day. The team would head back to Rafah — a move that typically requires coordination with Israel’s military.

At some point that evening, the World Central Kitchen workers piled into their vehicles. Their convoy — two armored vehicles and a third vehicle — left the warehouse and set out on a coastal road. The Israeli military had been informed of the aid workers’ movements, the charity said. They were heading south to their housing in Rafah, but they did not make it far.

The first reports of strikes in the area started coming in on Palestinian channels on the Telegram social media app about 10:30 p.m.

That’s when the Palestine Red Crescent, a humanitarian aid organization, got a call saying there had been an attack on a vehicle on Al-Rashid, the coastal road. The organization’s medics contacted the Israeli army to coordinate their own movement, said Mahmoud Thabet, who responded to the call.

Once the approval was granted, he said, they drove to the site and found three vehicles destroyed, along with the victims’ bodies.

“We had no idea who the victims were,” Mr. Thabet said in an interview. “We were shocked to see foreign individuals.”

Word that foreign workers had been killed started to emerge. Then later, photos of bloodied passports — British, Australian and Polish — along with images of broken bodies, circulated on social media.

Abdelraziq Abu Taha, another brother of Saif, said he had heard from a World Central Kitchen employee that there had been a strike near Deir al-Balah. Deeply worried, Mr. Abu Taha tried again and again to call his brother, but got no response.

There were no immediate public statements from World Central Kitchen or the Israeli military about what had happened. And more graphic images began to spread on social media: bodies being lifted out of an ambulance at Al Aqsa Martyrs Hospital and laid on the ground. Footage showed people taking photos and videos, jostling to get close, as passports were opened and placed on two corpses wearing bulletproof vests.

Just after 1 a.m., World Central Kitchen issued a short statement saying that it was aware of reports that members of its team had been killed in an Israeli military attack while working to support humanitarian food delivery efforts in Gaza.

Israel’s military responded soon after, saying at 1:34 a.m. that it was “conducting a thorough review at the highest levels to understand the circumstances of this tragic incident.”

The first confirmation that World Central Kitchen workers had been killed came 14 minutes later in a post on social media from Mr. Andrés. He mourned “several of our sisters and brothers” killed in an Israeli strike.

Messages of condolence, tributes and outrage poured in.

Abdelraziq Abu Taha kept trying to reach his brother, calling again and again until finally, someone picked up.

“The owner of this phone is in Al-Aqsa Martyrs Hospital,” he recalled a stranger’s voice saying on the line. The hospital had received five bodies, the stranger added.

It wasn’t until 7:07 a.m. that the scale of the tragedy became clear — seven workers had been killed, World Central Kitchen said in a new statement, placing the blame squarely on Israel’s military for what it called “a targeted attack.”

The Palestine Red Crescent said its medics had initially found five bodies at the scene. Two more were located later, after an hourslong effort, and taken to Al-Aqsa hospital, the organization said on Tuesday morning.

Photographs and videos of the aftermath that morning raised more questions about what had transpired on the coastal road. Three white trucks were in varying states of destruction, with the front of one burned down to its metal frame.

Charred papers bearing the World Central Kitchen emblem were scattered in the vehicle and on the roadway. Another vehicle’s passenger-side roof was pierced by a hole about two feet in diameter, but the windshield and side windows were virtually intact. The third vehicle’s doors, windows and roof were blown out, and its interior stained with blood.

Videos and photos verified by The New York Times suggested that the convoy had been hit several times. The imagery shows three destroyed white vehicles, with the northernmost and southernmost vehicles more than a mile and a half apart.

Weapons experts told The Times that the vehicles had each been struck by small, precise munitions, most likely fired from a drone. Chris Cobb-Smith, a security expert and British Army veteran, noted in a text message that the damage pattern suggested that the munitions had been “very accurate,” with a “devastating but limited blast.”

Justin Bronk, a senior research fellow with the Royal United Services Institute in London, reviewed videos showing the damaged vehicles. He noted in an email that they “appear to have been hit with small, highly precise missiles.”

“I can’t describe the shock when we saw those photos,” said Abdelraziq Abu Taha. “Even now, my father, my mother, none of us can believe it. He was under international protection. Only two hours earlier, he was by the Israelis at the pier.”

Reporting was contributed by Adam Rasgon, Kim Severson, Gaya Gupta, Matina Stevis-Gridneff, Michael Levenson and Anushka Patil.