An American Airlines flight bound for New York was stopped at San Francisco airport just before take-off, following an FBI tip-off of a possible hi-jacking attempt.

A witness said two passengers attracted suspicion after the threat was reported and were taken off the plane in handcuffs. But police later confirmed that no one was in custody and the FBI described the threat as “non-credible”.

American Airlines Flight 24 had been due to take off at 7.30am local time yesterday at San Francisco International Airport and was grounded at around 10am after a late departure from the gate.

Passengers were removed from the plane and taken by buses to a terminal where they were sent through security again.

An official said that the FBI in San Francisco recorded the threat as a potential hijacking.

The incident happened on a Boeing 767 that had already been delayed for more than two hours with 163 passengers and a crew of 11.

Passenger onboard described the incident as “pretty calm” and passengers with internet access searched the web for details about the incident.

Police eventually entered through the back door and arrested the two passengers.

Others on board were escorted off the plane and put on a buses. San Francisco Police Department officers screened them and their carry-on luggage with hand-held security wands.

The threat was originally by a clerk at a business in the city of Alameda, Lt Bill Scott told the Daily Mail. She told police how her business had received an anonymous phone call “making a threat specifically about Flight 24”.

“All passengers are safe and out of an abundance of caution, TSA requested the plane be moved to a remote location,” TSA spokeswoman Suzanne Trevino said.

The aviation industry remains on red alert following the attempted Christmas Day bombing of a Detroit-bound jet by a Nigerian Al Qaeda terrorist.