PARIS — An Air France flight from San Francisco to Paris was diverted to Montreal after an unspecified anonymous threat, and the passengers landed and disembarked safely before authorities declared it a false alarm.
At least 15 fire trucks and police cars met Flight 83 at Montreal's Trudeau International Airport late Monday, where authorities verified the aircraft, passengers and baggage.
Air France tweeted Tuesday: "after a full security search, false alert confirmed by local authorities following an anonymous threat."
Earlier, the airline had said the crew decided to divert "as a precautionary measure."
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 safely off the plane. She would not elaborate on the nature of the threat.
Airlines around the world face sporadic threats and occasionally divert planes as a result.
Tensions are unusually high in France, which has been in a state of emergency since Islamic extremist suicide bombings and shootings in Paris on Nov. 13 that killed 130 people, the deadliest attacks on French soil in decades.
"Everyone is pretty relaxed. There was no panic, no stress."
Passenger Gilles Raymond of San Francisco said after about five hours in the air, the pilot made an announcement that they needed to land in Montreal for technical reasons. He said once the plane had landed, the pilot said authorities would have to do a thorough security check of the plane and passengers and that everyone would have to disembark.
"Everyone is pretty relaxed," Raymond said while still inside. "There was no panic, no stress. Everyone is waiting in their seats. Some people are sleeping, and some are checking their phones or eating ice cream that the flight attendants gave them."
He said passengers spent at least an hour on board the plane during verifications.
"They told us they will check every passenger and that we may spend the night here," Raymond said.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier, nearly shirtless, tries to cross a fence, helped by security and police officers, after several hundred of employees invaded the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier (C), nearly shirtless, walks away from the crowd, helped by security and police officers, after several hundred of employees invaded the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier (C), nearly shirtless, runs away from the demonstrators, helped by security officers, after several hundred of employees invaded the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier, nearly shirtless, is taken away from the demonstrators by security officers, after several hundred of employees invaded the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Human Resources Director of Air France Xavier Broseta, shirtless, tries to cross a fence, after several hundred of employees invaded the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier (L), and Air France Executive Vice President Human Resources and Labour Relations, Xavier Broseta (R), shirtless, walk away from demonstrators, accompanied by anti-riot police officers, after several hundred employees stormed into the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier (2nd R), nearly shirtless, is led away from demonstrators by security officers, after several hundred employees stormed into the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Employees of Air France shout slogans and wave FO union flag (Workers' Force), inside the company headquarters in Roissy-en-France, on October 5, 2015, interrupting the launch of the plan at a central committee meeting.
KENZO TRIBOUILLARD via Getty Images
Demonstrators try to enter to Air France headquarters in Roissy-en-France, on October 5, 2015, during a demonstration for the launch of a restructuring plan at a central committee meeting.
KENZO TRIBOUILLARD via Getty Images
A woman holds a placard reading 'work yes, die no', during a demonstration in front of the Air France headquarters in Roissy-en-France, on October 5, 2015, during the launch of a restructuring plan at a central committee meeting.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier, nearly shirtless, is led away from demonstrators by security officers, after several hundred employees stormed into the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Air France's director of long-haul flights, Pierre Plissonnier, nearly shirtless, is helped by security and police officers to climb over a fence, after several hundred employees stormed into the offices of Air France, interrupting the meeting of the Central Committee (CCE) in Roissy-en-France, on October 5, 2015.
KENZO TRIBOUILLARD via Getty Images
Employees of French flag carrier Air France demonstrate near the company headquarters, during the launch of the plan at a central committee meeting, in Roissy-en-France, on October 5, 2015.
ASSOCIATED PRESS
Air France director of Human Ressources, Xavier Broseta, center left, and Air France assistant director long-haul flight, Pierre Plissonnier, center right, are protected by Air France security guards during scuffles with union activists inside the Air France headquarters at Roissy Airport, north of Paris, France, Monday, Oct. 5, 2015.
ASSOCIATED PRESS
Air France assistant director long-haul flight, Pierre Plissonnier, left, is protected by security guards as he flees the Air France headquarters at Roissy Airport, north of Paris, France, after scuffles with union activists. Monday, Oct. 5, 2015.
ASSOCIATED PRESS
Air France director of Human Ressources, Xavier Broseta, center (back to the camera), protected by security guards tries to flee the Air France headquarters at Roissy Airport, north of Paris, France, during scuffles with union activists, Monday, Oct. 5, 2015.
ASSOCIATED PRESS
Air France director of Human Ressources, Xavier Broseta, right, and Air France assistant director long-haul flight, Pierre Plissonnier, center, are protected by a police officer as they flee the company headquarters at Roissy Airport, north of Paris, after scuffles with union activist, Monday, Oct. 5, 2015.
ASSOCIATED PRESS
Air France union activists break through a gate as they storm the headquarters to disturb a meeting at Roissy Airport, north of Paris, France, Monday, Oct. 5, 2015.
ASSOCIATED PRESS
Air France director of Human Ressources, Xavier Broseta, center left, and Air France assistant director long-haul flight, Pierre Plissonnier, center right, are protected by security guards during scuffles with union activists inside the company headquarters at Roissy Airport, north of Paris, France, Monday, Oct. 5, 2015.
ASSOCIATED PRESS
Air France director of Human Ressources, Xavier Broseta, right, and Air France assistant director long-haul flight, Pierre Plissonnier, center, are protected by a police officer as they flee Air France headquarters at Roissy Airport, north of Paris, after scuffles with union activist, Monday, Oct. 5, 2015.
ASSOCIATED PRESS
Air France union activists stand on a table as they stage a protest during a meeting at the company headquarters at Roissy Airport, north of Paris, France, Monday, Oct. 5, 2015.
