The 'Snowden Effect': U.S. spies say militants change tactics

NSA whistleblower Edward Snowden, an analyst with a U.S. defence contractor, is seen in this still image taken from video during an interview by The Guardian in his hotel room in Hong Kong June 6, 2013. REUTERS/Glenn Greenwald/Laura Poitras/Courtesy of The Guardian/Handout via Reuters/Files

WASHINGTON (Reuters) - Even as U.S. intelligence agencies and their global partners assess potential damage from Edward Snowden's disclosures about surveillance programs, militants have begun responding by altering methods of communication, a change that could make it harder to foil attacks, U.S. officials say.

Intelligence agencies have detected that members of targeted militant organizations, including both Sunni and Shi'ite Islamist groups, have begun altering communications patterns in what was believed to be a direct response to details on eavesdropping leaked by the former U.S. spy agency contractor, two U.S. national security sources said.