U.S. B-2 stealth bombers and drones carried out attacks against two Islamic State military camps in Libya Wednesday night, killing more than 80 ISIS fighters who escaped from the city of Sirte last fall, Defense Secretary Ash Carter said Thursday.

The strikes used satellite-guided bombs, and targeted locations about 25 miles southwest of the city on Libya’s northern coast. Some Islamic State fighters fled to that location after Sirte was liberated from the terrorist group’s control late last year by Libyan government forces, with the help of U.S. airstrikes, in an operation dubbed “Odyssey Lightning.”