The Federal Bureau of Investigation said a flight bound for Dallas has returned to Philadelphia after law enforcement officials received a tip that liquid explosives could be on board.
FBI spokesman Frank Burton said US Airways Flight 1267 was called back to Philadelphia International Airport after officials received the anonymous tip.
Passengers were removed from the plane and bused away as law enforcement vehicles surrounded the aircraft. Video from TV stations showed law enforcement officials removing a person from the flight and police dogs on the tarmac.
Airport spokeswoman Victoria Lupica said there were 98 passengers on board. She said no other flights have been affected by the activity.
US Airways did not immediately return a phone message left by The Associated Press.