A fire at a military base in Alberta killed four soldiers and injured dozens, Prime Minister Mark Carney said Sunday, calling it one of the worst peacetime tragedies for Canada's armed forces.

Carney announced the deaths without detailing the cause of the fire at Canadian Forces Base Wainwright Saturday.

"Four service members have lost their lives, and their loved ones have been notified," Carney said in Ottawa, noting that dozens more were seriously injured.

"This is one of the worst tragedies the Canadian Armed Forces have experienced on Canadian soil in peacetime," he said.

A doctor at a hospital in Edmonton, about 200 kilometers (110 miles) northwest of the base, told public broadcaster CBC that Wainwright's health care facilities were overwhelmed by patients.

"It is more patients than any of us want to count right now," Warren Thirsk said. "It's a disaster. It's a 15- to 25-year disaster."

The Department of National Defence said the fire broke out about 4 p.m. Saturday in the base's training area.

The Municipal District of Wainwright said on social media the fire spread rapidly because of high winds. It later said the blaze was contained, though firefighters would continue to monitor the area.

"Military and civilian crews fought this fire throughout the night in some of the worst conditions imaginable, risking their lives to protect their fellow Canadians," Carney said.

The base is one of the largest of the Canadian Armed Forces, regularly hosting training exercises with NATO personnel.

"We will care for the injured through every step of their recovery," Carney said. "And we will stand by the women and men of our armed forces as they bear the weight of this loss; they will not carry it alone because in Canada we take care of one another."

The fire disrupted advance voting for Monday's vote on starting the process toward a referendum on Alberta's independence.

Alberta's provincial elections office said the advance voting station in Wainwright closed.