An EgyptAir official says a plane from Cairo bound for New York's John F. Kennedy airport has been forced to make an emergency landing after a passenger discovered a letter onboard threatening to blow up the aircraft.

Chairman of EgyptAir Tawfiq Assi says flight 985 had around 300 passengers onboard when it was diverted to Glasgow's Prestwick Airport on Saturday.

Britain's Ministry of Defense confirmed that it launched fighter jets to escort the plane to the Glasgow airport. Police in Glasgow confirmed that officers were responding to an incident but declined to provide further detail.

Assi says the flight is now being checked by a technical team that includes bomb disposal experts. Passengers were let off to wait in Glasgow's airport, and officials are also looking into their backgrounds.