CIA Director Mike Pompeo on Thursday said ISIS remains an "enormous threat" despite setbacks the terror group has suffered on the battlefield, including being driven from the group's self-declared capital of Raqqa.
"It is clearly the case that there are terrorists around the world who are intent upon using commercial aviation as their vector to present a threat to the West," the CIA director said in remarks at the Foundation for Defense of Democracies' National Security Summit in Washington.
Pompeo said the U.S. Department of Homeland Security has taken actions at airports in response to "perceived threats" to commercial airliners. Yet he said the terror risk still exists because it can be difficult to learn about attacks.
Fears of another 9/11-style attack were raised this week after comments attributed to the acting DHS secretary, Elaine Duke, in remarks at the U.S. Embassy in London. Her remarks were published Thursday in Britain's Express newspaper.
"The terrorist organizations, be it ISIS or others, want to have the big explosion like they did on 9/11," Duke said, according to reporting by Express. "They want to take down aircraft, the intelligence is clear on that."
Pompeo said bad actors willing to do harm to the West can go online to learn bomb-making skills from terrorists without ever getting on a phone or sending email. "Tools that we have developed to take down [terrorist] networks are less likely to be successful," he said.
"This is difficult stuff in a faraway place," Pompeo said. "This is a challenge for the intelligence community to figure out how that technology may have transferred."
The U.S. intelligence community was faulted by some for not anticipating the 9/11 attacks.
"We often talk about the things we know," Pompeo said. "I always remind everyone to remember the things that we simply may not see. Call them an intelligence failure, if you will."
Meantime, ISIS is on the run in the Middle East. Thousands of the terror group's militants have suffered, and the area the caliphate controls is a small fraction of what it once was.
"The fall of the caliphate is great news," the CIA chief said. "It is a historic achievement ... But it's partial at best."
Pompeo called ISIS "an incredibly difficult adversary" because of its ability to inspire and direct attacks from afar. Also, he said there's always a potential for ISIS to essentially morph into something else in the future.
"It would be foolish to predict that there was going to be no son of ISIS," he said. "You'd be betting against historical fact."
Some consider ISIS itself as an offshoot of al-Qaeda in Iraq. The two terror groups reportedly severed ties a few years ago.
"Whether they call themselves ISIS or ISIS 2.0 or whatever you want to call the name, this threat from radical Islamic terrorism is real," said Pompeo.
Pompeo said the global reach of ISIS and its followers is something that the U.S. continues to take seriously. He said ISIS or affiliates of the terror group operate in many regions other than the Middle East, including Southeast Asia.
He said the Internet continues to help the terrorist group recruit followers and conduct attacks.
"They still have the capacity to control and influence citizens all around the world," Pompeo said. "Technology enables it and their desire to even do these small-scale attacks."
The CIA chief said he's spent a lot of time with his counterparts in the U.K., which has suffered from several vehicle and other types of terror attacks this year. He said these attacks are often directed with help from abroad or with the aid of the Internet.
"I often hear folks talk about 'lone wolf,'" he said. "I prefer not to use that term because it is seldom the case that they were completely individual, acting autonomously. It's almost always the case that the ideology that drove them was driven by someone who had great intent to deliver that idea into their head."