“It’s not even close to being under control,” FBI Deputy Assistant Director Michael Steinbach told House members today.
“In many cases the information we have on foreign fighters traveling to the conflict zone stops when they get there,” Rasmussen warned.
Of the dozens of Americans who have gone to Syria or Iraq and trained with terrorists there, “a small group” of them have returned to the United States and are now being tracked by the FBI, sources previously told ABC News.
But today, Steinbach told lawmakers: "It would not be true if I told you that we knew about all of the returnees. … We know what we know.”
Nevertheless, authorities are “doing the best we can” to keep tabs on Americans and others traveling to Syria or Iraq, and to develop new “processes” to identify travelers, Steinbach said. He suggested automated searches of social media could help deal with the problem.
Steinbach described ISIS’ online efforts as “dangerously competent like no other group before,” using social media and other Internet forums “to both radicalize and recruit.”
Since the beginning of last month alone, ISIS has published more than 250 “official products” online, and those postings “reach wide and far almost instantaneously, with reposting and regeneration of follow-on links” in “an ever-growing number” of languages, according to Rasmussen.
Such a proliferation has spawned a new “blended threat,” bringing “foreign-fighter ideology” to homegrown extremists who have no real connection to terrorist groups overseas and are difficult to detect, Steinbach said.
“With the widespread horizontal distribution of social media, terrorists can identify sympathetic individuals of all ages in the United States – spot, assess, recruit, and radicalize either to travel or conduct a homeland attack,” Steinbach said. "A foreign terrorist now has direct access into the United States like never before."
Indeed, U.S. officials believe there are “a few hundred individuals” inside the United States who could be inclined to launch their own attacks, and the public should expect several – but fewer than 10 – “uncoordinated and unsophisticated plots” each year, Rasmussen said in a written statement submitted to the House committee before his testimony.
The head of Intelligence and Analysis at DHS, Under Secretary Francis Taylor, said such threats underscore the need for "increased vigilance" across government and in public.
Still, Steinbach said he has a “grave concern” over new phones and other devices being developed by the major tech companies, devices that allegedly leave no ability for authorities to collect information, even when a court approves it. The FBI has dubbed the growing issue “Going Dark.”
“This real and growing gap … must be urgently addressed because the risks of going Dark are great,” Steinbach, adding, "Without that lawful tool, we risk an attack."