FBI badge and gun. Photo: Wikipedia.

With as many as 1,000 active cases, Fox News has learned at least 48 ISIS suspects are considered so high risk that the FBI is using its elite tracking squads known as the mobile surveillance teams or MST to track them domestically.

“There is a very significant number of people that are on suspicious watch lists, under surveillance,” Republican Sen. Dan Coats said.

Read full story at Fox News.