A Delta Airlines flight that landed at a Denver airport was directed to a remote taxiway after an unspecified "potential security threat" onboard and passengers were ushered off the plane, but authorities later saw the threat as unlikely to be credible.

Flight 1500, a Boeing 737 with 151 passengers and six crew, landed roughly on time at Denver International Airport from Detroit Metropolitan Airport at about 4:40 p.m. Mountain Time (2240 GMT), airline spokesman Russell Cason said.

The passengers were quickly sent off the plane without their luggage and taken by bus to a separate part of the airport, where they were being interviewed by FBI officials. There were no reports of injury.

After screening passengers, crew and the plane, authorities said by 10 p.m. local time all travelers were allowed to collect their bags and go on their way, with no arrests made.

"We currently do not believe a creditable threat existed to the flight," said FBI spokesman Dave Joly.

Flight 1500 was thought to have a "potential security threat onboard the aircraft," Denver airport spokeswoman Julie Smith said, adding that all other airport operations were normal.

A local ABC News affiliate reported that a flight attendant found a note with a bomb threat. Joly said he could not confirm that report, adding that authorities were probing the "security concern" by screening passengers, luggage, and the plane.

Passenger Aaron Baratz told the Denver Post he and others were not allowed to open overhead luggage compartments to retrieve bags.

Tone Sevy, another passenger, posted a photograph on Twitter showing more than a dozen passengers returning to the idled jet on an empty stretch of runway to gather belongings. He said police with a dog were checking travelers, the buses, and the plane.

"Getting personal stuff off plane almost 2 hours later," Sevy tweeted. "Happy we are all safe." - Reuters