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A source at a telecom security firm contracting with the Department of Homeland Security has confirmed to CBS a report that it detected an unusual amount of suspicious cell tower activity affecting phones serviced by a "major" cell carrier in the vicinity of the White House and the U.S. Capitol.

DHS has not commented on the suspicious activity, but the source at ESD America, the security contractor, said the activity was first observed in January. It could indicate surveillance, possibly controlled by a foreign entity and potentially targeting specific lawmakers or officials given the geographic range.

"Mass amounts of location data appear to have been siphoned off by a third party who may have control of entire cell phone towers in the area," The Washington Free Beacon reported in its story breaking the news. "Such a tactic could be used to clone phones, introduce malware to facilitate spying, and track government phones."