Dozens of ex-prisoners head to Yemen after converting to Islam

The ‘radicalization’ of the individuals has alarmed US officials even though no evidence has tied them to terror activities.

According to a copy of the report obtained by The Associated Press, several of the individuals have "dropped off the radar" for weeks at a time and continue to carry US passports.

The assessment was written by staff of Senate Foreign Relations Committee Chairman John Kerry.

Kerry wrote in an introduction to the report, Al-Qaeda’s recruitment tactics also have changed. The group seeks to recruit American citizens to carry out terrorist attacks in the United States.