Two British men believed to be members of a notorious Islamic State group (IS) cell have been seized by Syrian Kurdish fighters. <br/><br/>US officials say, Alexanda Kotey, and El Shafee Elsheikh, were the last two members of the cell to remain at large. <br/><br/>The four members of the cell, all from London, were nicknamed "the Beatles" because of their British accents.<br/><br/>US officials said the execution cell had beheaded more than 27 Western hostages and tortured many more. <br/><br/>