The US Transportation Security Administration accidentally posted a document online containing secrets related to airport passenger screening practices, the Washington Post reported on Wednesday.
The TSA operating manual, posted on a federal procurement website last spring, spells out technical settings of X-ray machines and explosives detectors and other passenger and luggage screening details, the newspaper said.
TSA officials quoted by the Post confirmed the lapse, and former agency officials and congressional critics said the oversight exposed practices that were implemented after the September 11 attacks and following other security incidents.
"It increases the risk that terrorists will find a way through the defences," the Post quoted Stewart Baker, a former assistant secretary at the Department of Homeland Security, as saying.
The 93-page document also includes pictures of credentials used by US lawmakers, CIA employees and federal air marshals and describes when certain firearms are permitted past the checkpoint, said the newspaper.
The manual was posted on the Internet in redacted form but blacked-out passages were easily recovered, the Post quoted TSA officials as saying.
The newspaper quoted a second former DHS official as saying the mistaken posting of the secrets was more a public relations blunder than a security risk because TSA manuals are circulated widely in the aviation community.
TSA officials told the Post that the agency was conducting an internal review of the case.
"TSA has many layers of security to keep the travelling public safe and to constantly adapt to evolving threats. TSA is confident that screening procedures currently in place remain strong," the agency said in a statement.