A hijacking threat against a New York-bound flight that prompted federal authorities to isolate the plane in a remote area of San Francisco International Airport for three hours Thursday turned out to be a hoax, authorities say.

The 163 passengers aboard American Airlines Flight 24 were kept in their seats while cable TV news networks aired long-distance shots of the Boeing 767-300 as it was parked on the tarmac - all because of what turned out to be a "non-credible" phone threat to an Alameda hotel clerk, police said.

Eventually, everyone onboard was questioned, taken by bus to the domestic terminal and allowed to book other flights, said Lt. Lyn Tomioka, a spokeswoman for San Francisco police.

Although two passengers were led away in handcuffs, they were quickly freed, and no one was arrested. Officials noted that the threat was a federal crime.

The plane was on the verge of taking off for John F. Kennedy International Airport just before 10 a.m. when it was diverted at the request of the FBI and the Transportation Security Administration.

Federal agents acted after Alameda police told them of a call that had been made shortly after 9 a.m. to the Hampton Inn and Suites hotel on Harbor Bay Parkway.

A hotel clerk reported that a man, whose voice she did not recognize, had made a threat concerning Flight 24. FBI Special Agent Joe Schadler said the caller threatened a hijacking and had specific information about the flight.

Onboard the plane, the pilot told the passengers over the intercom that there was a "credible security threat," said a passenger, 43-year-old Jay Sears of Rye, N.Y.

"It was a little tense," he said.

Rachel Sklar, 33, of Mountain View, was aboard the flight with her husband and two young children, bound for a New York vacation. She said passengers had been ordered to stay in their seats and had not been served food, but were eventually allowed to use the restrooms.

Passengers were told they could not use their laptop computers or iPads but were permitted to use cell phones.

Many sent text messages, including Michael Anderson, 20, who was flying back for football practice at Yale. He had been dropped off at the airport by his mother, Anne Anderson, 51, of Palo Alto.

At 10:12 a.m., she got a message from her son saying, "They're basically not letting anyone stand up at all. It's really weird."

Shortly before 1 p.m., San Francisco police boarded the plane, and passengers finally were allowed to leave.

Tomioka confirmed that a man and a woman were taken off the rear of the plane in handcuffs, but provided no explanation. They were not arrested, she said.

Everyone else on the plane was escorted out the front in groups of six. They were questioned one at a time and had their bodies and carry-on luggage checked with handheld scanners before boarding airport buses.