Fifty investigators are examining a fire at a Canadian military base that killed four soldiers and injured 39 others, Prime Minister Mark Carney said Monday, as questions grow over why training continued even though officials knew a fire was burning nearby.

Speaking in Parliament in Ottawa, Carney said that the investigation into Saturday's tragedy at Canadian Forces Base Wainwright in Alberta was being led by the Canadian Forces National Investigation Service, with support from the Royal Canadian Mounted Police.

Lawmakers observed a moment of silence prior to Carney's address to the House of Commons, with opposition party leaders likewise paying tribute.

“A fire was burning in the training area.

Propelled by ferocious winds, the fire advanced nearly a kilometer in under a minute, reaching the location where soldiers were gathered,” Carney said.

He stated that investigators had not yet determined what had ignited the grass fire.

“We will get the answers to what caused this terrible tragedy, as expeditiously and transparently as necessary,” Carney later told reporters.

The fire overwhelmed soldiers from the 3rd Battalion, Princess Patricia's Canadian Light Infantry, along with Army reservists who were conducting live-fire training.

As of Monday, nineteen of the injured remained in critical condition.

Conservative opposition leader Pierre Poilievre, who represents Wainwright in Parliament and was visiting the town, said many had sustained severe burns requiring weeks or months of intensive care.

He warned that their lives might never be the same.

Maj. Gen. Wade Rutland stated on Sunday that military officials had been aware of the fire for hours but believed it to be contained, permitting training to proceed until the winds abruptly shifted.

Approximately 84 soldiers from Charlie Company were undergoing training at two locations, one dedicated to grenade throwing and the other to practising assaults on simulated enemy positions.

The fire swept into the second area.

Carney said the soldiers were preparing for a mission the following spring to reinforce Canadian troops serving with NATO in Latvia.

Rutland said investigators would examine whether winds had driven the flames toward the soldiers or whether the fire had spread unseen through the vegetation.

They would also examine whether military safety procedures needed to be changed.

The military identified those killed as Sgt. Morgan Wong of Edmonton; Pvt. Shaun Farrell of Prince Albert, Saskatchewan; Pvt. Aidan Goulding of North Vancouver, British Columbia; and Pvt. Hayden Lykkemark of Langley, British Columbia.

Carney remembered Goulding as someone who willingly embraced difficult challenges, and Wong as someone upon whom his family could always rely.

He said Farrell and Lykkemark were best friends and that Lykkemark had harboured a dream of a career in law enforcement.

Poilievre recalled having met Goulding during the Canada Day celebrations at the base in July, when a group of young soldiers approached him requesting a photograph.

Following Saturday’s tragedy, someone sent him the picture identifying Goulding as one of those killed.

Poilievre also said he had heard accounts of soldiers who ran toward the flames to help their comrades, characterizing their actions as extraordinary acts of courage.

Military liaison officers were providing assistance to families at hospitals in Edmonton, Calgary, Red Deer and Wainwright.

Mental health teams and chaplains were likewise offering support to soldiers and their families.

Carney ordered that flags be lowered to half-staff on all federal buildings nationwide on Sunday in honor of the four soldiers killed.

Flowers were laid at Wainwright’s century-old war memorial, a stone clock tower commemorating soldiers who lost their lives in past conflicts.

The tower withstood a devastating fire that ravaged downtown Wainwright in 1929.

“They were training to defend Canada. To serve Canada. Now, Canada serves them,” Carney said.