Ben Carson: Flying Planes Into Twin Towers 'Didn't Require a Great Deal of Sophistication'

— -- Republican presidential candidate Dr. Ben Carson doubled down on his previous language this morning, saying that al Qaeda was not an existential threat to the United States in 2001 and 2003.

Today, he told ABC News that ISIS is more of a threat now than al Qaeda was in 2001 and 2003.

"They weren’t nearly as developed as they are now -- at that point,” Carson said in response to an ABC News question. "That was my point. This is so much greater a threat than that was.”

Carson also said the attacks on the World Trade Center in 2001 "didn’t require a great deal of sophistication.”

“Yeah, but being responsible for the Sept. 11 attacks, what happened right there really didn’t require a great deal of sophistication because we were not paying attention,” Carson told ABC News. "We were not coordinating our efforts so you didn’t have to be all that great, you had to be able to fly some planes and get a couple of people in here. That’s going to be a lot more difficult to do now. You’re going to have to be a lot more sophisticated than that now.”

On Sunday, the retired neurosurgeon kicked off his rally in Nevada by holding a moment of silence for the victims of the Paris attacks followed by some brief remarks on foreign policy.

In explaining his call for military muscle in Iraq and Syria, Carson said that al Qaeda was not an “existential threat” in 2003.