U.S. President Joe Biden told Israeli Prime Minister Benjamin Netanyahu that U.S. support for his war in Gaza depends on new steps to protect civilians, a shift in position for the American leader, who has faced increased pressure to take a harder line against Israel amid mounting deaths.

The warning, delivered in a Thursday phone call between the two leaders, signaled that Biden is toughening his stance after an Israeli strike that killed seven people delivering food to displaced Palestinians in Gaza. Biden called the incident "unacceptable,” according to a White House description of the conversation.

Hours later, the prime minister’s office announced that the country’s security cabinet had authorized action to bolster assistance and "prevent a humanitarian crisis.”