CIA insider on ISIS' influence: "Success breeds followers"

Officials are becoming increasingly worried by the pace at which the Islamic State of Iraq and Syria (ISIS) has successfully spread their following. With allegiances forming in Egypt, Algeria and Afghanistan, more than 1,000 miles away from the terror group's base, their influence is taking hold faster than al Qaeda's ever had.

"As long as there's a perception that they are winning, as long as they are doing well there, their brand is going to continue to spread," senior security contributor and former CIA deputy director Michael Morell said. "Success breeds followers in this business."

Monday, an American drone strike in Afghanistan killed a former Taliban commander who had previously been held in Guantanamo Bay and was believed to have become a top ISIS recruiter. While air strikes have continued over the last six months, Morell said there's still more to be done.

"The only thing we can do is take the fight to these guys in Iraq and Syria," he said.

Tuesday, Syria's President Bashar Assad said that he has been made aware of U.S.-led airstrikes against the extremist group inside his country. The coalition that includes four Arab nations has been conducting an international campaign against ISIS and its followers.

Those countries have been successful in stopping ISIS' "blitzkrieg across Iraq," but Morell said to be effective, up to 100,000 troops would need to be deployed to fight ISIS on the ground.

"The idea, of course, is to train Iraqi troops to be able to conduct this fight," Morell said. 'That training is going fairly slowly at the moment."