(CBS News) As the discussion over wiretapping and foreign hacking still dominates the conversation in Washington, an unusually high amount of suspicious cell phone activity in the nation's capital has caught the attention of the Department of Homeland Security, raising concerns that U.S. officials are being monitored by a foreign entity.

The issue was first reported in the Washington Free Beacon, but a source at telecom security firm ESD America confirmed the spike in suspicious activity to CBS News.

ESD America, hired preemptively for a DHS pilot program this January called ESD Overwatch, first noticed suspicious activity around cell phone towers in certain parts of the capital, including near the White House. This kind of activity can indicate that someone is monitoring specific individuals or their devices.

DHS confirmed the pilot program but did not comment on the suspicious activity.

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