Canadian police said officers were responding to a "mass casualty collision" near the town of Carberry, west of Winnipeg.
At least 15 people were killed after a minibus carrying elderly people on their way to the casino crashed into an articulated lorry in central Canada's Manitoba province on Thursday.
Ten other people were injured and hospitalised, some of whom are in a critical condition.
Canadian police said on Twitter that officers were responding to a "mass casualty collision" near the town of Carberry, west of Winnipeg, and that first responders and other Royal Canadian Mounted Police units were on the scene.
"My heart breaks hearing the news of the tragic accident near Carberry. My most sincere condolences go out to all those involved," tweeted Manitoba's premier Heather Stefanson.
Authorities are investigating the cause of the accident, the worst of its kind Canada has experienced in years.
In 2018, 15 people were killed in an accident in the neighbouring western province of Saskatchewan, when a truck collided with a bus carrying young ice hockey players.