All departing flights at Vancouver International Airport were put on hold for more than two hours Sunday morning after a security guard noticed what appeared to be a prohibited item on the screen of an X-ray machine.

The bag in question had already left the screening point, and a decision was made to re-check the passengers, said Renee Fairweather with the Canadian Air Transport Security Authority.

She said it wasn't clear what the object was, but prohibited items include liquids and sharp objects. A firearm would have shown up clearly on the screen.

Boarding gates at the airport were closed as departing passengers went through a second screening. Flights were not allowed to take off for about two hours and 15 minutes, causing major line-ups at the airport.

Incoming flights could land during the clampdown, but people were not allowed off the planes.