 The account itself is operated by a man with the "nom de guerre" Sheik Yoonis, who has in the past responded to press questions during telephone interviews in a "clipped British accent".Most of al-Shabaab's messages on Twitter are in English, with authorities suggesting that they are intended for an outside audience and potential recruits in the West.Officials in the United States, where Twitter is based, are exploring legal ways to terminate the account, although they acknowledge that doing so might raise free speech concerns.