(CNN) -- A passenger with diplomatic credentials of Qatar was detained Wednesday night after a disturbance aboard a United Airlines flight en route to Denver, Colorado, federal authorities said.

Initial reports were that the incident involved an attempt to set a shoe on fire, but there were later indications that the situation may have resulted from a misunderstanding involving smoking during the flight.

The passenger was in a lavatory and may have been smoking, a U.S. official said. He also may have made an "unfortunate comment" referring to a shoe bomb when questioned on the plane, the official said.

Fran Townsend, a former homeland security official under President George W. Bush, said that the person involved was a Qatar diplomat and that her sources said the incident may in fact have been a misunderstanding. She said law enforcement officials examined the man's shoes and were satisfied there were no explosives.

The Boeing 757 carrying 157 passengers and six crew members took off from Reagan National Airport in Washington.

Two F-16 fighters responded to the incident and intercepted the United jet, escorting it to the Denver airport. The United flight landed safely at approximately 6:50 p.m. (8:50 p.m. ET).

Crew members asked law enforcement officials to meet the plane, said United spokesman Mike Trevino. The FBI has responded to the incident.

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"The situation is under control," said one of the law enforcement officials, who spoke on condition of anonymity.