Threat grounds US passenger jet
An American Airlines flight bound for New York City was halted at San Francisco just before take-off, following a threat against the plane.
The threat was later described by the FBI as non-credible, but it rattled nerves in San Francisco and beyond and marked the latest in a series of airline scares in the past year.
A witness said two passengers in the back row attracted suspicion after the threat was reported and were taken off the plane in handcuffs. But a law enforcement official later said no one was in custody.
American Airlines Flight 24 had been due to take off at 7.30am local time on Thursday 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.
It was not clear if it was a bomb or hijacking threat, but a second law enforcement official who received an investigative update on the case said it was not credible.
The official said the FBI in San Francisco recorded the threat as a potential hijacking. The threat was relayed more broadly throughout the FBI as a potential bombing.
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. It finally pulled away from the gate at 10am, only to taxi to a remote section of the tarmac where passengers sat for another two hours.
"There was no fear in the cabin at all," passenger Michael Kidd said. "It was pretty calm. Even with the frustration of having to sit there, there were no raised voices."
Passengers with internet access searched the web for details about the incident. Flight attendants admonished passengers who tried to get up and reach their overhead luggage, Mr Kidd said. Police eventually entered through the back door and arrested the two passengers.