US President Joe Biden spoke with Israeli Prime Minister Benjamin Netanyahu by phone, their first call since an Israeli airstrike killed seven aid workers in Gaza. The call between the two leaders was less than half an hour in duration. 

Biden emphasized to Netanyahu that strikes on humanitarian workers and the humanitarian crisis in Gaza are "unacceptable," according to the readout of the call provided by the White House.

One of the World Central Kitchen employees killed in the strike was a dual US-Canadian citizen, with victims also including three British and one Australian national, a Polish citizen and a Palestinian.

"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," the readout added.    

Biden said "US policy with respect to Gaza will be determined by its assessment of Israel's immediate action on these steps." 

In addition, the US president said an "immediate cease-fire is essential" in Gaza and urged Netanyahu to reach a deal "without delay" to bring hostages trapped in Gaza home.