The FBI is using elite surveillance squads and more than 500 FBI agents to track 48 high-risk ISIS suspects in the U.S., the Daily Mail reports. 
The agents are working around-the-clock in the event that a terrorist attack is planned.
“There is a very significant number of people that are on suspicious watch lists, under surveillance,” Republican Senator Dan Coats, who is on the Select Committee on Intelligence, said.
Coats added that it “takes enormous amounts of manpower” to follow the suspects constantly and is costing the authorities dear.
“It is a big resource drain. Yes it is. Almost overwhelming,” Coats said.
“There will be a lot of people over the Thanksgiving weekend that will not be enjoying turkey with their family. They’ll be out there providing security for the American people and the threat is particularly high during this holiday period,” he added.