(Sia: Combo reports from WaPo & the BBC & Reuters.
This is truly terrible! My deepest condolences to everyone affected. I hope the huge number of injured survive their injuries and that American hospitals offer assistance in treating those injured as Canadian hospitals are overwhelmed. My daughter said that her well equipped trauma unit in a huge Maine hospital are offering assistance, prepared, and awaiting an answer regarding possible transfers.)

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Canadian Prime Minister Mark Carney said a “violent, fast-moving” fire swept through the base in Alberta.

The Canadian military said in a statement to media outlets that the incident remains under investigation but that, at this time, “there are no indications that it was the result of any terrorist activity.”

He said Sunday the Canadian flag will fly at half-mast on federal buildings across Canada.

The fire started in a training area of the base around 4 p.m. Saturday and “spread rapidly” beyond its boundaries, Canada’s Defense Department said in a statement.

“As emergency responders continue their work and the situation continues to evolve, the full extent of the impact remains under assessment,” the department’s statement read.

Giuseppe Cavo Dragone, the chair of NATO’s military committee, shared condolences in an online statement: “Wainwright is where Canadian soldiers, and so many Allies with them, train for the hardest tasks of our profession. Those who fell there served our common security, and the Military Committee will honour their memory.”

Ambulances are lined up outside Wainwright Health Centre after the deadly blast at Canadian Forces Base Wainwright.

Several people have been killed or injured as a result of a large fire near a Canadian military base in Alberta, the nation's military has said.

The Canadian Armed Forces (CAF) said the full extent of the incident was being assessed and that details of casualties and injuries would not be made public until that was complete.

Canadian TV network Global News reported that at least seven were killed and dozens more injured when a gas line or gas well was hit during a live-fire training exercise, citing unnamed military sources.

Canadian Forces Base Wainwright, where the fire broke out at about 16:00 local time (22:00 GMT) on Saturday, is one of the country's busiest military training bases.

On Sunday morning, a defence department spokeswoman told the BBC that "the situation continues to evolve" and "the full extent of the impact remains under assessment".

She also said investigations are in progress but "at this time, there are no indications that it was the result of any terrorist activity".

Defence Minister David McGuinty earlier said the CAF and local authorities were managing the fire, describing the situation as "very, very active and delicate".

Canada's Prime Minister Mark Carney said his "thoughts are with all the brave women and men affected".

The Canadian Broadcasting Corporation (CBC) said Royal Alexandra Hospital in Edmonton had declared a code orange, a disaster response protocol for responding to a high-casualty incident.

Warren Thirsk, an emergency department doctor there, told the broadcaster that the number of patients would otherwise "overwhelm" Edmonton's healthcare facilities.

"It is more patients than any of us want to count right now. It's a disaster. It's a one in every 15 to 25-year disaster."

After the fire erupted on Saturday, it "spread rapidly due to high winds" and tore through the fences of the base, the Municipal District of Wainwright said.

The region experienced gusts of up to 100km/h (62mph), though local officials indicated fire crews had contained the blaze.

McGuinty told reporters he "cannot recall an incident like this in recent memory".

Local authorities have urged residents to avoid the area and give all emergency vehicles right of way.

The mayor of the nearby town of Wainwright, Bruce Pugh, said it was a "heavy day" for his community.

"We have neighbours who are either serving or former members of the Canadian Armed Forces. We're integrated, our kids play in the same hockey teams, attend the same schools," he told CBC.

While details on the impact of the fire remain unclear, Pugh said he believed this would come to be the area's largest-ever mass casualty event.

Google Canadian Forces Base Wainwright entrance at the end of a road, with a sign on the right hand side of the roadGoogle
Canadian Forces Base Wainwright is a busy military training base used for live-fire exercises
Gen Jennie Carignan, chief of Canada's defence staff, said it was a "profoundly difficult moment" for the CAF.

Neighbouring provinces have mobilised in support. Saskatchewan Premier Scott Moe said he had deployed resources to Alberta and was "ready to provide more if required", while British Columbia Premier David Eby said his government had offered "all possible assistance".

Wainwright is the main base used by the Canadian military for live-fire training exercises, according to CBC, with about 690 military personnel and 300 civilian workers on-site on a typical day.