CIA director: ISIS engaged in "active external plotting"

There is no "credible evidence" that militants within the Islamic State of Iraq and Syria (ISIS, also known as ISIL) are plotting strikes against the United States to coincide with the 13th anniversary of the 9/11 terrorist attacks, CIA Director John Brennan said Wednesday. But he emphasized that the U.S. intelligence community remains exceptionally vigilant should that possibility arise.

"I think there's active external plotting," Brennan told CBS News Homeland Security Correspondent Bob Orr in an interview, which will air in full on the "CBS Evening News" on Wednesday night. "I think this is one of the things that ISIL has tried to do is that they have not just focused on one particular area. ...So we are watching this very, very carefully and we need to continue to maintain pressure on them and to prevent them from even starting to move down the execution timeline."

Last month, President Obama authorized targeted airstrikes against the militant group as it swept toward northern Iraq, where American military, diplomats and civilians are stationed. The U.S. military now plans on gradually expanding its air campaign against ISIS, not only in Iraq but also Syria, once targets are identified. There will also be an increase in the number of American military personnel on the ground in Iraq.

ISIS, which has steadily territory in Iraq and Syria throughout the year, recently beheaded two American journalists as a warning to the United States against interventionism. As President Obama prepares Wednesday to lay out his strategy going forward to combat the group, Brennan says one thing he's worried about is retaliatory strikes against the West.

"We are working very closely with our partners - security, intelligence, others - in the region and throughout the world to make sure that we're able to monitor whatever types of attempts they're going to make," Brennan said. He noted they're specifically watching for any opportunities they have " to leverage all of those foreigners who have traveled to Iraq and Syria and turn them around, to go come back, to Europe or the United States."

Following the 9/11 attacks, then-CIA Director George Tenet famously reflected that in hindsight, "the system was blinking red." Brennan channeled that quote to underscore the gravity of ISIS's rise and to call for a "collective call to action" globally.

"It's blinking red from the standpoint of it is moving at a pace and at a rate that threatens the region as a whole and seriously raises concerns about its ability to export its violence beyond the region, including to this homeland," he said. "So I think the lights may be blinking red as far as it is time to make sure that it's not able to continue along its current path."