According to a new report from The Boston Globe, federal air marshals are tracking American citizens who are not currently under investigation or on a terrorist watch list by way of a previously unknown Transportation Security Administration (TSA) program.

The program is called “Quiet Skies,” which directs federal air marshals to track Americans on domestic flights who may be affiliated with someone on a watch list or whose travel patterns mirror those of suspected terrorist. Individuals being tracked through Quiet Skies are not suspected of any crimes, according to the Globe.

“The program analyzes information on a passenger’s travel patterns, and through a system of checks and balances, to include robust oversight, effectively adds an additional line of defense to aviation security,” TSA said in a statement provided to The Verge.

marshals track if a passenger uses a computer, fidgets, or sleeps

Travelers are tracked by officials as they move about the airport, and once they board, a small team of marshals follows them onto the plane. Documents obtained by the Globe noted an extensive observation process in which marshals make note of whether a passenger uses a computer, fidgets, or even sleeps.

The report pointed out that thousands of unsuspecting citizens have been targeted by the program and around 35 passengers are tracked each day. The TSA argues that gathering intelligence on citizens is not the purpose of the program. In a statement, the TSA said that Quiet Skies “is not intended to surveil ordinary Americans,” but so that “passengers and flight crew are protected during air travel.”

“With routine reviews and active management via legal, privacy and civil rights and liberties offices, the program is a practical method of keeping another act of terrorism from occurring at 30,000 feet,” TSA said in a statement.

The air marshal program is already expensive, and it provides few security benefits to justify its $1 billion budget. There is a bill moving through Congress, sponsored by Rep. Jody Hice (R-GA), that would require the TSA to be more transparent with its spending and provide congressional committees with information about its effectiveness in preventing terrorist attacks.