Denver International Airport spokeswoman Laura Coale says Frontier Airlines flight 601 from Knoxville landed safely at 7:30 p.m. Mountain time Friday and was moved to a remote location.
She says in a recorded statement that the FBI and police responded because of "a possible security threat on board," and one person was taken into custody.
Coale says a police bomb squad also responded, but did not provide any more information on the nature of the possible threat.
Other passengers were interviewed by authorities.
Media reports say there were 136 passengers and five crew members aboard.