SALT LAKE CITY — U.S. Rep. Jason Chaffetz is defending his proposal to prohibit U.S. airport screeners from using imaging machines that can look through clothes to detect weapons or explosives.

The Utah Republican told The Salt Lake Tribune in Washington that he believes technology is available that can identify explosives without invading the public's privacy.

Chaffetz's comments came after Umar Farouk Abdulmutallab was charged with trying to destroy a jetliner that had taken off from Amsterdam and was bound for Detroit. Abdulmutallab hid an explosive under his clothes that might have been detected by the scanners Chaffetz wants to ban.

"It's a difficult balance between protecting our civil liberties and protecting the safety of people on airplanes," Chaffetz said Sunday. But, "I believe there's technology out there that can identify bomb-type materials without necessarily, overly invading our privacy."

Chaffetz' bill has passed in the House, but is languishing in the Senate.

Chaffetz said there are plenty of other law enforcement tools, such as heat sensors, that can detect weapons or explosives. Chaffetz also notes that his bill would ban only primary use of the body imaging machines; screeners would be able, under his bill, to send a passenger through the machines as a secondary screening tool.

Chaffetz said because Abdulmutallab was on a government watch list, he should have been subjected to further screening.

Abdulmutallab was on a broad U.S. terrorist watch list but he was not designated for special screening measures or placed on a no-fly list because of a dearth of specific information about his activities, Homeland Security Secretary Janet Napolitano said Sunday. She said he was properly screened before getting on the aircraft in Amsterdam.