What we're seeing is an increase in the evolutionary pace of IED (improvised explosive device) design, ... It's increasing at a pace we previously haven't seen.

What we're seeing is an increase in the evolutionary pace of IED (improvised explosive device) design. It's increasing at a pace we previously haven't seen.

We believe that this signifies this is a warning message, and they feel they're obligated (to give) in the run-up to an attack.

If you shut it down, it will be back in about five seconds in a million other locations.

They could have simply been told, 'Enter the United States, learn how to fly these types of planes,' ... They may not have known ultimately where this was headed or what the goal was. Then as that became necessary, they could have been in communication with other members of other cells who would have given them other directions.

They would want people that could get into the country -- preferably legally, preferably people we weren't aware of. They don't have a history with the intelligence services of law enforcement.