Three people were taken to hospital with non-life-threatening injuries after a United Express plane with more than 30 people on board slid off the runway at Ottawa's Macdonald-Cartier International Airport Wednesday afternoon.

Flight 8050 from Washington landed around 2:30 p.m. local time, about a half hour later than scheduled. It was overcast and raining at the time of the incident.

Witness Steph Nicholds, who was watching the runway while listening to airport scanners, said the landing at first appeared to be smooth.

"It's been raining most of the afternoon, the runway was very slick," Nicholds, a pilot-in-training, told CTV News Channel in a telephone interview.

"The pilot reported, just as he was coming down towards the end, he said ‘I'm going off the edge of the runway,' and he did. There was no traction at all."

"With the runway conditions, I'm actually very impressed with him," she added.

The plane was carrying 33 passengers and three crew members, who were all taken off the plane within 20 minutes of it coming to a stop, reported CTV's Catherine Lathem in Ottawa. The pilot suffered minor neck and back injuries and the co-pilot sustained a minor leg injury. One passenger was taken to hospital with an undisclosed minor injury.

Images from the scene show the plane sitting off to the side of the end of a runway, its nose on the ground, with two fire trucks beside it.

Lathem said some of the passengers reported feeling "a real jolt" during the incident. Passenger John Hardaway said it felt as if the plane had made a hard right turn.

Three investigators from the Transportation Safety Board are on scene investigating the accident's cause, Lathem said. It may be weeks or even months before they complete their investigation, she said.

Trans State Airlines, which was operating the flight on behalf of United Airlines, will also conduct an investigation.

Paul Benoit of the Ottawa Airport Authority said it is too early to speculate about what may have caused the plane to leave the runway, though passengers said the weather or a brake problem may have been factors.

All other flights were able to take off and land as scheduled at the airport, officials said.

A flight status update at the United Airlines website said the return flight to Washington, scheduled to leave Ottawa at 2:27 p.m., had been cancelled.

With files from The Canadian Press