CALGARY – A bomb threat believed to be a hoax prompted WestJet to divert a Vancouver-to-Toronto flight to Calgary on Wednesday night.

WestJet said flight WS722 landed safely and the 30 passengers and five crew members on board exited the aircraft via stairs.

The airline said it had diverted the Boeing 737-700 “out of an abundance of caution” and later said the flight had been “cleared as safe by Calgary police” and no explosive device was found.

WestJet said the passengers were to continue to Toronto on other flights later in the evening.

This was the fourth time in five days that a WestJet flight had been the subject of a threat and it was the fifth such incident involving a Canadian airliner in a week.

On Tuesday, a WestJet flight with 113 passengers and five crew members landed on a flight from Toronto to Saskatoon landed at Saskatoon following a threat but police say a search of the aircraft found no bomb.

A WestJet flight en route from Edmonton to Toronto was forced to divert to Winnipeg on Monday night because of an unspecified threat. Six passengers suffered minor injuries during the evacuation.

Last Saturday morning, a WestJet flight from Edmonton to Halifax landed in Saskatoon after police said a call had been made claiming an explosive device was on board.

And, last Thursday, St. John’s International Airport was temporarily closed because a note was found in the washroom of an Air Canada flight that authorities considered a potential bomb threat.

In all of the cases, searches of the aircraft unearthed nothing suspicious.

Police say the investigation is continuing and there have been no arrests.