ROMULUS, Mich. - Federal authorities say an American Airlines co-pilot has been detained at Detroit Metropolitan Airport after he was suspected of being drunk.

The Federal Aviation Administration said the co-pilot was held from a Saturday morning flight from Detroit to Philadelphia. He's suspected of having a blood-alcohol level above the legal limit.

The pilot was detained at a security checkpoint after arriving for the flight at the airport in the Detroit suburb of Romulus.

American Airlines spokeswoman Laura Nedbal said in a statement that the flight was cancelled and the airline was putting customers on other flights.

Airline officials declined to discuss the co-pilot or his condition but say it's assisting local law enforcement agencies.