Multiple people dead in explosion during live-fire military training exercise

Multiple people were killed and dozens more were injured when an explosion erupted at a Canadian military base, according to authorities.

The deadly blast occurred on Saturday afternoon at the Canadian Forces Base (CFB) Wainwright in Alberta province, igniting a massive fire that was fanned by high winds and spread from the sprawling military facility into the surrounding rural area, Canadian officials said.

During a news conference on Sunday, Canadian Prime Minister Mark Carney said at least four service members were killed in the blast and subsequent "violent fire," and that "dozens more are seriously wounded."

Carney called the incident "one of the worst tragedies for the forces on Canadian soil in peacetime."

Citing multiple military sources, the Canadian Global Television Network's Global News reported earlier on Sunday that at least seven people were killed and dozens more were injured.

"I cannot recall an incident like this in recent memory," Canadian Minister of National Defense David McGuinty said during a news conference on Saturday night at the military base near the small town of Wainwright.

The cause of the explosion is under investigation, military officials said. Asked to provide details, McGuinty would only say that "this is a very, very active and delicate situation."

In a statement on Sunday, the Canadian Department of National Defense said, "There are no indications that it was the result of any terrorist activity."

Multiple Canadian Armed Forces sources told CGTV's Global News that the incident occurred during a live-fire training exercise, and that a gas line or a gas well was struck and ignited the explosion.

A fire erupted within the training area of the military base around 4 p.m. local time on Saturday, officials said.

"The fire spread rapidly beyond the boundaries of the training area, while military and civilian emergency services responded quickly to control that fire and to support those affected by this tragic event," the Canadian government said in a statement Sunday morning.

Carney said his office is gathering information on the "serious incident that triggered a large-scale fire" at a military base.

"Our thoughts are with all the brave women and men affected," Carney said in a social media post.

Alberta Premier Danielle Smith said in a social media post that the "significant and tragic" incident is affecting many military personnel.

Neither Carney nor Smith provided details about what caused the fire.

Admiral Giuseppe Cavo Dragon, chair of the NATO Military Committee, also addressed the incident in a social media post on Sunday, saying, "Canada does not carry this grief alone. All 32 Allied Chiefs of Defense stand with you and the Canadian Armed Forces."

"Wainwright is where Canadian soldiers, and so many Allies with them, train for the hardest tasks of our profession," Dragon said. "Those who fell there served our common security, and the Military Committee will honor their memory."

One of Canada's largest and busiest military training bases, CFB Wainwright is where soldiers train for combat operations, military officials said. The base is home to the Canadian Manoeuvre Training Center, which conducts realistic battlefield exercises.

ABC News' Chris Barry, Matthew Holroyd and Michael O'Keefe contributed to this report.