The TSA security manual which was posted by mistake in federal procurement website contained details on technical settings of X-ray machines and explosives detectors, including screening details on passenger and luggages.
In addition to that it also reveals pictures of credentials used by US lawmakers, CIA employees and federal air marshals, gives description on procedures for giving check point permit to certain firearms.
Former Agency officials and Congressional critics said the documents exposes the security measures adopted by US prior to the Sep 11, 2001 attack.
"It increases the risk that terrorists will find a way through the defenses," Stewart A Baker, a former assistant secretary at the Department of Homeland Security, was quoted in media report.
TSA officials said that the matter is under investigation.
"TSA has many layers of security to keep the traveling public safe and to constantly adapt to evolving threats. TSA is confident that screening procedures currently in place remain strong," the agency said.