Hayden's comments came during a speech he gave Sunday at an adult education forum at St. John's Episcopal Church, across the street from the White House, The Washington Post reported.
"Gmail is the preferred Internet service provider of terrorists worldwide," Hayden said, adding, "I don't think you're going to see that in a Google commercial, but it's free, it's ubiquitous, so of course it is."
During the speech, Hayden justified NSA surveillance programs by saying the Internet was created in the United States.
"We built it here, and it was quintessentially American," he said, adding that partially due to that, much of traffic goes through American servers where the government "takes a picture of it for intelligence purposes."
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