'I was just in a plane crash. Oh my God': Witnesses recount escape in Toronto

"Our plane crashed. It's upside down."

These were the words of John Nelson, a passenger on a Delta Air Lines flight that had just crashed and flipped while landing at Toronto Pearson International Airport.

All 80 people on board the flight from Minneapolis - 76 passengers and four crew - have survived, the airport's chief executive has said.

Eighteen people were injured but only a small number are thought to be seriously hurt, and investigators are looking into what caused the crash.

"Most people appear to be okay. We're all getting off," Mr Nelson said in a video posted to Facebook soon after the incident.

"We skidded on our side, then flipped over on our back," he said, adding that "there was a big fire ball out the left side of the plane".

Like Mr Nelson, Ashley Zook took immediately to social media to express her disbelief, filming herself saying: "I was just in a plane crash. Oh my God."

Mr Nelson said he was able to unbuckle himself and push himself to the ground. "Some people were kind of hanging and needed some help... and others were able to get down on their own," he said.

Mr Carlson said passengers quickly acted as a team. "What I saw was everyone on that plane suddenly became very close, in terms of how to help one another, how to console one another."

Video footage shared on social media shows people clambering out of the overturned aircraft, with fire crews spraying it with foam.

Passengers were seen being helped out of the plane's doors by airport staff, with some then running away from the plane's entrance.

Despite a plane flipping on the runway, Diane Perry said she learned of the crash when her family called her while she was in line to check her luggage.

The reason for the crash is not yet clear. Two runways will remain closed for several days for investigation and passengers have been told to expect some delays.

That sentiment was echoed by Mr Carlson, who said it was "really amazing" to be alive, while sporting a cut on his head. "I'm a little balder than I was this morning," he said.