Former members of the 9/11 commission have warned that despite efforts to make American cities safer from terrorist attacks, the US remains vulnerable to cyberterrorism and "lone wolf" attackers.
Committee members said the US had failed to protect itself in at least three key areas and must develop better bomb detection technology, improve radio equipment to allow police and fire services to better communicate and introduce a national identification card that could help prevent terrorists trying to slip into the country.
Former Illinois governor James Thompson said he feared terrorists from afar could hack into computers, crippling banks, businesses and key utilities while throwing the nation into disarray.
"You read stories day after day about some 18-year-old Romanian hacker getting in and playing havoc with banks, public offices, so think about what some of the rogue state actors might be doing," he said.
He said the nation remained vulnerable to "lone wolf" terrorists who act on their own, sharing their plans with no-one and therefore beyond the reach of being detected by intelligence-gathering agencies beefed up after 9/11.
"The lone wolf operative, a single person, radicalised by what they see on the internet or hear at mosques, is going to be a greater threat to the US today than on 9/11," he said.
Mr Thompson and eight other members of the 10-member 9/11 commission, who disbanded in 2004 after recommending steps the nation could make to ward off terrorism, gathered on the Indiana University campus in Bloomington for a two-hour discussion before about 800 students and others.
The wide-ranging discussion included several commissioners recalling the important role that the families of those who died in the terrorists attacks in New York, Washington and Pennsylvania played in prodding the US Congress to form the panel.
Mr Thompson also said that hijackers like those who crashed planes in New York, Washington and Pennsylvania could still get state IDs today, despite efforts to create uniform standards for identification.
He said the 9/11 Commission's 2004 report called for federal identification standards, but that those had not succeeded because of civil liberties concerns and states' desire to guard their own processes.