U.S. Defense Secretary Pete Hegseth said on Friday that the United States has launched a military operation against Islamic State militants in Syria, in response to an attack near Palmyra earlier this month that killed three Americans.

In a post on X, Hegseth said U.S. forces had begun an operation dubbed “Falcon Eye,” targeting Islamic State fighters, infrastructure and weapons storage sites across Syria, describing it as a direct response to the Dec. 13 attack on U.S. personnel.

“Our country, under President Donald Trump’s leadership, will never hesitate to defend its people,” Hegseth said, adding that the operation had killed “many” Islamic State members and would continue.

Later on Friday, President Donald Trump said the United States was carrying out “very strong strikes” against Islamic State strongholds in Syria, calling the campaign a tough response to the killing of U.S. troops by the group.