CIA Director John Brennan on Sunday said in an interview broadcast late Sunday that it is “inevitable” that the Islamic State in Iraq and Syria (ISIS) will try to carry out attacks in the United States.

“I’m expecting them to try to put in place – the operatives, the material or whatever else that they need to do or to incite people to carry out these attacks, clearly,” Brennan said on CBS’s “60 Minutes.”

“So, I believe that there attempts are inevitable,” he added. “I don’t think their successes necessarily are.”

Brennan said the intelligence agency knew in the days leading up to the November attack in Paris that the terrorist group was planning to strike somewhere.

“We knew just in the days before that ISISL was trying to carry out something,” he said, using an alternate acronym for the group.

“But the individuals involved have been able to take advantage of the newly available means of communication that are – that are walled off from law enforcement officials,” he added, referring to encryption technology.

He said U.S. intelligence has prevented “numerous” ISIS attacks from taking place so far.

“Believe me, intelligence security services have stopped numerous attacks – operatives that have been moved from maybe the Iraq to Syria theater into Europe,” he added.

“They have been stopped and interdicted and arrested and detained and debriefed because of very, very good intelligence.”