Updated

SAN JUAN, Puerto Rico (AP) — A man on a flight from West Africa to New York City was removed from the plane and detained Thursday after authorities apparently added him to a no-fly list during the trip.

Customs and Border Protection agents detained the man while the Delta Air Lines jet stopped to refuel in San Juan, Puerto Rico after an overnight trip from Dakar, Senegal. The flight originated in Nigeria, the native country of a man accused of boarding a Detroit-bound airplane from Amsterdam in December with a bomb hidden in his underwear.

The man detained in Puerto Rico was not immediately charged with any crime. Customs and Border Protection issued a statement identifying him only as "potential person of interest," who was removed from the flight for questioning.

But passengers told The Associated Press that the captain announced over the intercom that the man had been added to a roster of people banned from travel to the U.S. while the plane was in flight.

The captain described the passenger as a "serious security risk," said Joan Mower, a passenger from Washington.

"The good news is nothing happened, we're all safe," said Mower, a former Associated Press reporter, now director of development for Voice of America. "The question is how does a guy who is on the no-fly list get on a plane ... and Delta only hears about it over the Atlantic."

The man, a citizen of Gambia, was not on the no-fly list when he boarded the aircraft in Dakar, said a U.S. official who spoke on condition of anonymity because he was not authorized to discuss the issue publicly.

It was not clear what triggered suspicions about the man. U.S. officials typically do not confirm whether or not any specific individual is on the no-fly list and, for security reasons, do not discuss what factors might lead someone to be banned from travel to the U.S.

The flight continued on without incident to New York's John F. Kennedy International Airport after the man was removed from the plane.

Passenger Nbaye Beye said the man, who appeared to be in his late 20s, appeared nervous when approached by a U.S. agent but got off the plane quietly.

"The other passengers were nervous but everyone was sitting calm and cool," another passenger, Hassane Diallo, told Associated Press Television News.

Delta vetted all passengers as required, checking to see if any are on a no-fly list, when the plane took off from Senegal, said spokeswoman Susan Elliott.

Flight 215 had taken off from Abuja, Nigeria on late Wednesday and stopped in Dakar early Thursday before heading to New York. Delta said the diversion to Puerto Rico was to refuel. Elliott said such a diversion is not unusual for a full flight that runs into trans-Atlantic headwinds and was not related to the detention of the passenger.