The FBI is using elite surveillance units to monitor at least 48 Islamic State suspects in the United States who are considered particularly high risk.

Hundreds of suspected ISIS sympathizers in the U.S. are being monitored, but the FBI is using special units to monitor the most serious suspects, reported Fox News. Units of at least a dozen FBI agents monitor the suspects 24/7.

“The FBI together with law enforcement agencies across the country are engaged in this,” Republican Sen. Dan Coats, who is on the Select Intelligence Committee, told Fox News. “It takes [an] enormous amount of manpower to do this on a 24-7 basis. It takes [an] enormous amount of money to do this.”

“There will be a lot of people over the Thanksgiving weekend that will not be enjoying turkey with their family,” he added. “They’ll be out there providing security for the American people and the threat is particularly high during this holiday period.”

There are as many as 1,000 active ISIS suspects in the U.S. currently. About 250 Americans have traveled or tried to travel to Syria this year, according to FBI Director James Comey, and many of them are plotting to help ISIS.

The number of live cases bolsters the concerns of some lawmakers about the possibility of ISIS operatives infiltrating the U.S. via the refugee resettlement program. The Obama administration has announced a minimum of 10,000 Syrian refugees will be resettled in the U.S. in the next two years.

“Whether or not the individuals are affiliated with a foreign terrorist organization and are willing to travel abroad to fight or are inspired by the call to arms to act in their communities, they potentially pose a significant threat to the safety of the United States and U.S. persons,” Comey told the Senate Committee on Homeland Security and Governmental Affairs in October.

The FBI has charged several people across the country this year for crimes related to ISIS. After the ISIS attack in Paris earlier this month, world leaders are meeting to see what can be done about the growing threat.

http://dailycaller.com/2015/11/27/dozens-of-islamic-state-suspects-warrant-247-fbi-surveillance/