Ahmed “Amu” Dabbashi, the 28-year-old leader of a militia in this seaside town near the Tunisian border, proudly unfurls a black Islamic State flag, seized during late-February raids on safe houses of ISIS, as the group is also known. He shows me a captured arsenal, too: truck-borne explosives, detonators, crates of ammo, crew-served machine guns, and identification cards of foreign fighters.