ISIS-Inspired Attack Could Come without Warning

Government officials are deeply concerned about the threat ISIS poses in the United States and that it's getting worse. The recent deadly assault on a cartoon exhibit in Texas has only heightened the alarm.

Now, a top CIA veteran is warning that it's only a matter of time before the jihadist group launches a 9/11-style attack on American soil.

"If we don't get ISIS under control, we're going to see that kind of attack," Michael Morrell, former acting director of the CIA, said in a USA Today interview.

U.S. Secretary of Homeland Security Jeh Johnson said Americans should continue to go to public events, but be vigilant at the same time. 

Last week the Pentagon ordered U.S. military bases to upgrade their force protection condition status because of concerns about ISIS.

Public officials say one reason the terror group poses such a threat is because of its clever use of social media.

"We're very definitely in a new environment because of ISIL's effective use of social media, the Internet -- which has the ability to reach into the homeland and possibly inspire others," Johnson said on ABC's "This Week" show.

California Sen. Dianne Feinstein, the top Democrat on the Senate Intelligence Committee, said the United States should not underestimate ISIS' social media power. She's especially concerned about the trend of ISIS leaders encouraging sympathizers around the world to carry out attacks for which the group then claims responsibility.

"It is putting the lone wolf in a position [that says] you do it and we take credit for it," Feinstein told NBC's "Meet the Press."

Some lawmakers are also concerned that a recent ruling against the National Security Agency and its collection of phone records will hamper the country's ability to counter ISIS.

On ABC's "This Week," Sen. Richard Burr, D-N.C., said, "It's really simple. That turns us back to pre-9/11."

Some public officials say the restrictions on phone record collections, together with the Internet and lone wolf actors, means an ISIS-inspired attack could come without warning.

That's why vigilance is a key ingredient for law enforcement and the public.