Counterterror Officials: Terror Chatter on the Rise During Holiday Travel Season

Dec. 21, 2010— -- With the busy holiday travel season already in motion, the nation's top counterterror officials are seeking to assure the public of their efforts to safeguard the homeland even as they acknowledge real dangers.

In a wide-ranging interview with ABC's Diane Sawyer yesterday, Secretary of Homeland Security Janet Napolitano, Director of National Intelligence James Clapper, and Chief Counterterrorism Advisor John Brennan said that though they know of no specific, credible threat against the U.S. at this time, there are plenty of warning signs to keep them on alert.

"There is a lot of chatter in the intel world ... that references the holidays," said Napolitano. "We know that things have already happened in Europe, and we're watching that very closely as well. But yes, there is increased chatter in the system. And there are increased efforts undertaken now by ... homeland security."

Watch Diane Sawyer's interview with counterterrorism officials tonight on "ABC World News."

On Christmas Day one year ago, Umar Farouk Abdulmutallab, a Nigerian-born, apparent al Qaeda operative, allegedly attempted to destroy a Northwest Airlines flight.

Abdulmutallab was able to board an aircraft with explosives concealed in his underwear, despite being on a terror watch list, and attempts by his father to alert U.S. officials that he was a danger. Only his fellow passengers were able to prevent him from detonating the device.

Officials say that a year later, new security measures would have prevented Abdulmutallab's attempted attack.

"We would prevent him from getting on that plane from Amsterdam to Detroit," said Napolitano. "That's more international protocols put in place ... new international aviation requirements."

"We identified deficiencies in the system," said Brennan. "We have learned lessons from these examples of attempted attacks. And we now, I think, are having a much stronger system as a result."