Denver airport officials say hundreds of bags were loaded onto airplanes in late December without being run through security scanners.
Denver Airport Manager of Aviation Kim Day told KMGH-TV in Denver that the incident involved "a couple thousands of bags over a couple of days." The breach was first reported by the station.
The Transportation Security Administration said it is investigating, but that it appeared the incident was an unintentional human error.
Day said passengers weren't in any danger because no one could have known their bags were not scanned.
"No one checking in could have known that their bag was not going to be checked so you could not have used this to foil the system," Day said.
KMGH said it obtained records showing the breach started on Christmas Day and lasted for seven days. The station said an airport memo indicates the bags bypassed scanners because of a human error in programming a computer.
The station said records and interviews indicate the unscanned bags went on United Airlines flights. A United spokeswoman told The Associated Press on Monday she could not verify the report. She declined to comment further.
In a written statement, TSA told the station it took steps to ensure the error was corrected and that additional safeguards were put in place.
TSA and airport officials didn't immediately return calls from the AP on Monday.
Information from: KMGH-TV, http://www.thedenverchannel.com
© Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.