A Transportation Security Agency (TSA) worker runs her hands over the head of a traveler during a patdown search at Denver International Airport, the day before Thanksgiving November 24, 2010. REUTERS/Rick Wilking

WASHINGTON (Reuters) - President Barack Obama defended controversial new security measures at U.S. airports in an interview released on Friday, saying the methods were necessary to prevent a potential terrorist attack.

Some Americans have objected in recent weeks to the use of revealing full-body scanners and extra-thorough patdowns at airport security checkpoints.

“This is going to be something that evolves. We are going to have to work on it,” Obama told ABC’s Barbara Walters, according to a transcript provided by the network.

“I understand people’s frustrations with it but I also know that if there was an explosion in the air that killed a couple of hundred people ... and it turned out that we could have prevented it possibly ... that would be something that would be pretty upsetting to most of us -- including me.”

The United States tightened screening at airports in the wake of the September 11 attacks by al Qaeda militants in 2001 but the new security measures follow several recent threats.