A counterterrorism expert said that Iranian sleeper cells might be hiding "in plain sight" waiting to target more rural areas ...

NewsNation national security contributor Tracy Walder says while the concept of Iranian sleeper cells in the U.S. is not new, there may have been a recent influx of agents. Walder says they are ...

Sleeper Cell, released in 2005, followed an undercover FBI agent trying to infiltrate a terrorist group - and it's streaming right now.

A few months later, cameras watch her in a New York coffee shop where she meets with someone she thinks is her Russian handler. It is really an undercover FBI agent.

Sleeper cells comprised of spies or terrorists hiding out in the U.S. or Western countries, remain inactive, often living quiet and unassuming lives working regular jobs until they are ordered to ...

Those in sleeper cells may live normal lives until triggered to act violently.

US warns sleeper cell threat is rising amid tensions with Iran Former FBI agent: Sleeper threats may enter through US borders Public urged to stay alert; DHS issues worldwide caution warning ...