The specially-trained officers patrol terminals monitoring passengers for suspicious body language and facial expressions.
Since 2006, the officers have been stationed at more than 160 airports across the US in order to provide a hidden measure of security.
But 16 people accused of being part of terrorist plots have passed through US airports undetected a total of 23 times since 2004 - a number of them since the scheme was started - according to an investigation by the Government Accountability Office.
Earlier this year, officials at the Transportation Security Administration (TSA), which runs the behaviour detection programme, asked US Congress to expand the scheme, which is known as Spot - Screening Passengers by Observation Techniques.
John Mica, a Republican congressman from Florida who was involved in setting up the TSA in response to the Sept 11, 2001 terrorist attacks, said it had become too bureaucratic.
He said the report into behaviour detection would further call into question the agency's ability to perform its security mission.
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