The accident happened when a small bus and truck collided at a highway junction and the bus caught fire.
The crash occurred at the junction of two major roads near the town of Carberry in southwestern Manitoba, 170km (105 miles) west of Winnipeg. The bus passengers had been on their way to a casino in Carberry, CBC News reported, citing a casino spokesperson.
“We’ve been able to establish that at least 15 people have been confirmed deceased as a result of this collision,” said Assistant Commissioner Rob Hill, who commands the Manitoba Royal Canadian Mounted Police.
Hill told a televised news conference that “sadly, this is a day in Manitoba and across Canada that will be remembered as one of tragedy and incredible sadness”.
Nirmesh Vadera, who was working at a business on the side of the highway when the crash happened, said he saw the bus on fire in the grass on the side of the road, and rescue teams trying to extricate people from the burning vehicle.
“It was burning and all the [firefighters] and medical help and everybody was trying to get them away from the fire,” he said.
The bus had been carrying about 25 people, and police said 10 people were being treated in hospital.
Police said the drivers of both vehicles were alive, and declined to say who might have been responsible for the crash.
TV broadcasters aired images of what looked like a large van or bus smouldering in a ditch near a truck with a smashed engine on a road. The road was littered with debris – broken glass, a large bumper and what looked like a walking aid. Blue and yellow tarpaulins were also stretched out.
In a tweet, Prime Minister Justin Trudeau said he sent his “deepest condolences to those who lost loved ones today, and I’m keeping the injured in my thoughts. I cannot imagine the pain those affected are feeling,” he said.
“My heart breaks hearing the news of the tragic accident near Carberry,” Manitoba Premier Heather Stefanson said on Twitter.
In neighbouring Saskatchewan, 16 people died in April 2018 after a truck hit a bus transporting a junior hockey team on a rural road. The truck driver was sentenced to eight years in prison in 2019.
The worst traffic accident in Canadian history occurred in 1997 when a bus plunged into a ravine in the province of Quebec, killing 44 people.