A Paris-bound flight that departed from San Francisco International Airport was diverted to Montreal late Monday following an "anonymous threat," the airline confirmed. Passengers on the plane told NBC Bay Area the flight was diverted due to a bomb threat.

Overnight, Air France wrote in a tweet that local authorities conducted a "full security search" and confirmed that the plane was safe.

AirFrance spokeswoman Nathalie Hedin sent an email about the "anonymous threat," without referencing the word bomb, adding that the airlines diverted the plane to Montreal "as a precautionary measure."

Air France Flight 83 departed from San Francisco at 3 p.m. Monday and originally was scheduled to arrive at Charles de Gaulle/Roissy airport in Paris at 10:35 a.m. Tuesday. No threat was found, and the plane took off for Paris on Tuesday morning, the airline stated.

Hedin said an investigation will be conducted to try to find out the source of the threat, and apologized for any inconvenience to its passengers.