U.S. Air Force fighters were scrambled and escorted two civilian flights one to New York and other bound for Detroit after passengers spent “an extraordinary time in the bathroom”, mirroring the heightened precautions in force following a terror alert.

Two F-16 fighters escorted and shadowed the flights until they landed safely at New York’s Kennedy Airport and Detroit’s Metropolitan Airport after the crew of the two flights sounded an alarm, reporting suspicious activity on board, CNN reported.

Three passengers were taken off in handcuffs from the Frontier Airline’s flight from Denver as it landed in Detroit, but no charges were filed, the channel reported quoting airport spokesman Scott Winter.

Mr. Winter said that the Frontier flight 623 with 116 passengers on board had been put on “flight alert” after the crew complaint that three passengers had spent extraordinary long time in the bathroom.

The Airbus 318 plane was escorted to a secluded bay on the remote part of the airfield as police SWAT teams boarded it.

Similarly, crew sounded flight danger signal on board a New York City bound flight.

The FBI said North American Aerospace Defence Command scrambled F-16 fighter jets to shadow the two planes “out of an abundance of caution”.

New York police has been in an heightened state of alert after Homeland department said a credible but uncorroborated tip had been received of a car bomb plot on the 10th anniversary of the 9/11 attacks in either New York or Washington.

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