The U.S. military launched large-scale strikes against dozens of Islamic State targets in Syria on Friday in retaliation for an attack on American personnel, U.S. officials said.

A U.S.-led coalition has been carrying out airstrikes and ground operations in Syria targeting Islamic State suspects in recent months, often with the involvement of Syria’s security forces.

President Donald Trump had vowed to retaliate after a suspected ISIS attack killed U.S. personnel last weekend in Syria.

Defense Secretary Pete Hegseth said the strikes targeted “ISIS fighters, infrastructure, and weapons sites” and that the operation was “OPERATION HAWKEYE STRIKE.”

“This is not the beginning of a war — it is a declaration of vengeance,” Hegseth said. “Today, we hunted and we killed our enemies. Lots of them. And we will continue,” he added.