MONTREAL: A semi-trailer truck and a bus carrying seniors collided in central Canada's Manitoba province on Thursday, killing at least 15 people and injuring 10 more, authorities said.

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.

"What I can confirm right now is that a bus carrying approximately 25 people collided with a semi at the intersection of Highway One and Highway Five," RCMP Manitoba officer Rob Hill told reporters, adding most of the people in the minibus were elderly.

"Fifteen people have been confirmed deceased," while 10 others were transported to hospital with various injuries, he said.

Hospitals in the region confirmed they were responding to large numbers of victims and that all facilities were on alert.

The crash occurred on the Trans-Canada Highway north of Carberry.

Several tarps were laid on the ground, apparently covering some of the victims, according to the Canadian Broadcasting Corporation, which said witnesses described a burned vehicle in a ditch near the highway.

According to Nirmesh Vadera, who works near the accident site in a roadside hotel restaurant, numerous emergency vehicles and two helicopters were at the scene of the crash, which occurred around midday.

"It was really, really surreal to see the extent of (the accident), because I've never seen this kind of fire on any vehicle," Vadera told AFP by telephone, adding there was lots of smoke visible around the site and dozens of emergency responders were on the scene.

"The news from Carberry, Manitoba is incredibly tragic," Canadian Prime Minister Justin Trudeau said on his official Twitter feed, adding he was sending his "deepest condolences" to those who lost loved ones.

"I can't imagine the pain you're feeling, but Canadians are here for you," he said.

"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.

She said flags at the province's legislative building have been lowered to half-staff "out of respect for those we have tragically lost."

Authorities said the highway was closed in both directions and they were asking motorists to avoid the area.

"There were people all over the place, some looked like they were getting medical attention," truck driver Josh Carson, who had driven past the accident site, told Global News television.

"It for sure looked like a pretty bad one."

Thursday's crash echoes a 2018 tragedy in which 15 people were killed in an accident in the neighboring western province of Saskatchewan when a truck collided with a bus carrying young ice hockey players.