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.”