An Air France flight from San Francisco to Paris was diverted to Montreal after an unspecified anonymous threat, and the passengers have landed and disembarked safely, an airline official said Tuesday, AP reported. At least 15 fire trucks and police cars met the plane, and Canadian authorities were verifying the aircraft, passengers and baggage. Air France said an investigation will be carried out into the origin of the threat, and promised to send passengers safely to their destinations. Spokeswoman Ulli Gendrot said all passengers were off the plane within a few hours of landing. The airline said in a statement Tuesday morning that the crew of Flight 83 decided to divert "as a precautionary measure" and landed just before midnight Montreal time.