FBI says it disrupted activities of dozens of potential IS recruits

An Islamic State flag flies over the custom office of Syria's Jarablus border gate as it is pictured from the Turkish town of Karkamis, in Gaziantep province, Turkey August 1, 2015. REUTERS/Murad Sezer

WASHINGTON (Reuters) - FBI counterterrorism agents followed dozens of potential militants around the United States full time over the summer and disrupted activities pursued by many of them, FBI Director James Comey told a congressional committee on Thursday.

Comey also told the Senate Committee on Homeland Security and Governmental Affairs that U.S. investigators knew of many U.S.-based Islamic militant suspects who used encrypted communications.