US officials: Violent extremists turning to private communications

FILE - In this March 26, 2015 file photo, House Homeland Security Chairman Rep. Mike McCaul, R-Texas speaks on Capitol Hill in Washington. U.S. law enforcement officials expressed concern Wednesday about the growing use of encrypted communication and private messaging by supporters of the Islamic State, saying the technology was complicating efforts to monitor terror suspects and extremists. (AP Photo/Lauren Victoria Burke, File) (The Associated Press)

U.S. intelligence officials are warning about the growing use of encrypted communication and private messaging by supporters of the Islamic State.

The officials told a House committee on Wednesday that such modes of communications are complicating law enforcement efforts to keep tabs on extremists and terror suspects.

John Mulligan, the deputy director of the National Counterterrorism Center, said in his prepared remarks that one of the two men involved in an attempted terror attack in Garland, Texas urged fellow Islamic State supporters before the shooting to move their communications to private Twitter messages.

Michael Steinbach, the head of the FBI's counterterrorism division, said changing technology is outpacing laws that allow the FBI to intercept communications.