Shahidullah Shahid : More and more terrorist and insurgent groups are swearing loyalty to ISIS . In 1998 , ISIS has attracted some half dozen groups , he says . And ISIS has continued to expand its geographical reach . Bergen ' perceived success is attracting these recruits , ISIS says .
Shahidullah Shahid : More and more terrorist and insurgent groups are swearing loyalty to ISIS . In 1998 , ISIS has attracted some half dozen groups , he says . Bergen ' perceived success is attracting these recruits , ISIS says .