Air France said two flights bound from the United States to Paris were diverted Tuesday night after threats were received. One of the flights had taken off from Dulles International Airport in Virginia, and the other had taken off from Los Angeles.

Both airplanes landed safely, the airline said: the Dulles flight in Halifax, Nova Scotia; and the Los Angeles flight, in Salt Lake City.

According to a Twitter posting from the airline, both flights were “subjects of anonymous threats.” Twitter messages sent late Tuesday by the Royal Canadian Mounted Police in Nova Scotia referred to a “bomb threat.”

It was not immediately clear late Tuesday night who made the threats and who received the messages. The mounted police Twitter feed said details of the threat would be “part of the investigation.” An airport spokeswoman in Salt Lake City said the threat was made by telephone.

In its Twitter message, the airline said that “as a precautionary measure,” the two flights were diverted. The aim was to permit authorities to conduct all needed security checks, the airline said.

Emergency vehicles are parked near an Air France plane that was diverted to Salt Lake City International Airport Tuesday. (Ravell Call/Ravell Call/The Deseret News via AP)

The Dulles flight, Air France Flight 55, carried 298 passengers and crew members, according to an account from the Canadian Broadcasting Corp. The mounted police said later Tuesday night that the number of passengers and crew members had been revised to 262.

The plane that left Dulles was a Boeing 777. The flight from Los Angeles, Air France Flight 65, was on an Airbus A380, and CNN reported that it carried 497 passengers.

The passengers in Nova Scotia were deplaning and were being taken to a secure location, the CBC reported. It was not clear how many were Americans or residents of the Washington region.

Also unclear was how or whether they might continue their trip.

Peter Spurway, a spokesman for Halifax Stanfield International Airport, told CBC that he was waiting to hear whether Air France would send a plane to pick them up.

In the meantime, he said, they were being made as comfortable as possible.

Craig Vargo of the airport police in Salt Lake City told a television station there that the FBI was investigating the Airbus, using dogs to check for explosives.

The dogs were going over the plane and the passengers’ luggage, according to KUTV, Channel 2. The passengers were in the terminal, the station said.

A passenger on the Los Angeles flight was quoted on the CNN Web site as saying that the pilot announced that the plane had to make an emergency landing.

The passenger, Trevor Moran, said that “everyone on the flight is waiting in this lobby,” after leaving the plane. He said, “Nobody knows what’s going on.”

Another passenger on Flight 65 said passengers were being interviewed by the FBI. He said that he had just finished dinner aboard the Airbus when trays were abruptly taken away by crew members who said the plane was landing because of “unsafe flying conditions.”

Flights on several airlines have been disrupted in recent days because of security concerns. The concerns have heightened in the wake of the terrorist attacks in Paris.