President Joe Biden told Israeli Prime Minister Benjamin Netanyahu that the killing of aid workers and the ongoing humanitarian crisis in Gaza is "unacceptable" during the first phone call between the two leaders since seven World Central Kitchen employees, including one American, were killed in an Israeli Defense Forces airstrike.

Biden "made clear the need for Israel to announce and implement a series of specific, concrete, and measurable steps to address civilian harm, humanitarian suffering, and the safety of aid workers," a readout of the phone call released by the White House read. "He made clear that U.S. policy with respect to Gaza will be determined by our assessment of Israel's immediate action on these steps."

Seven World Central Kitchen employees from the United Kingdom, Australia, Poland, North America and Gaza were killed in an airstrike that the charity's founder José Andrés described as "targeted." They were traveling in a clearly marked vehicle, after coordinating with the Israeli government, to deliver food to the starving Palestinians who are trapped inside the besieged Gaza Strip.

In the six months since the October 7 Hamas attacks, the situation inside Gaza has grown increasingly dire. At least 33,037 Palestinians have been killed, including more than 13,000 children. People in northern Gaza are subsisiting on an average of 245 calories per day, according to Oxfam International. The region is also considered the most dangerous place in the world for journalists and aid workers.

"This was not just a bad luck situation where 'oops' we dropped the bomb in the wrong place," Andres told Reuters. "This was over a 1.5, 1.8 kilometers, with a very defined humanitarian convoy that had signs in the top, in the roof, a very colorful logo that we are obviously very proud of," he said. It's "very clear who we are and what we do."

National security spokesperson John Kirby told reporters that Biden and Netanyahu's phone call last around 30 minutes. Kirby confirmed that the president was increasingly dissatisfied with Netanyahu's failure to adhere to the U.S.'s warnings about the humanitarian situation.

"What we want to see are some real changes on the Israeli side. We don't see changes from their side," Kirby said. "There's been growing frustration."

The president also reportedly emphasized the need for a ceasefire in Israel's War on Gaza and "urged the Prime Minister to empower his negotiators to conclude a deal without delay to bring the hostages home."

Biden and Netanyahu also discussed threats that Iran has made against Israel, with the president reiterating that the United States supports Israel.