Continuing to deal with terrorism with an "iron hand", the government on Tuesday designated 18 more individuals as "terrorists" including chief of the banned Hizbul Mujahideen Syed Sallahuddin, founders of Indian Mujahideen Bhatkal brothers and a close lieutenant of underworld don Dawood Ibrahim, Chhota Shakeel, taking the total number of such proscribed persons to 31.