“[ISIS] will probably attempt to conduct additional attacks in Europe, and attempt to direct attacks on the U.S. homeland in 2016,” Stewart said during testimony.
NSA Director James Clapper, who was also testifying, warned ISIS is using the refugee stream from Iraq and Syria to disguise fighters and to transfer them into the United States. This is the same tactic intelligence has seen used a number of times throughout Europe. ISIS has also been using refugee camps to recruit new fighters.
Further, Clapper confirmed ISIS has in fact produced and used chemical weapons in Iraq.