Fifty investigators are looking at a fire at a Canadian military base.

The fire killed four soldiers.

It hurt 39 other people.

Prime Minister Mark Carney said this on Monday.

People are asking why training went on.

Officials knew a fire was burning nearby.

Carney spoke to Parliament in Ottawa.

He said the Canadian Forces National Investigation Service leads the investigation.

The Royal Canadian Mounted Police help them.

The fire happened on Saturday.

It was at Canadian Forces Base Wainwright in Alberta.

Carney said a fire was burning in the training area.

Strong winds pushed it almost a kilometer.

This took less than a minute.

It moved toward soldiers standing together.

He said investigators do not know what started the grass fire.

Later he spoke to reporters.

He said the government would get answers.

It would be as quick and open as needed.

The fire caught soldiers from the 3rd Battalion, Princess Patricia's Canadian Light Infantry.

Army reservists were also doing live-fire training.

Nineteen injured people were in critical condition on Monday.

Opposition leader Pierre Poilievre represents Wainwright in Parliament.

He said many had bad burns.

They need weeks or months of intensive care.

Maj. Gen. Wade Rutland spoke on Sunday.

He said officials knew about the fire for hours.

They believed it was contained.

So training went on.

Then the winds suddenly changed.

About 84 soldiers from Charlie Company were training at two places.

The fire swept into the second area.

Carney said the soldiers were getting ready for a mission next spring.

The mission will strengthen Canadian troops with NATO in Latvia.

The military named the dead soldiers.

Sgt. Morgan Wong was from Edmonton.

Pvt. Shaun Farrell was from Prince Albert, Saskatchewan.

Pvt. Aidan Goulding was from North Vancouver, British Columbia.

Pvt. Hayden Lykkemark was from Langley, British Columbia.

Carney ordered flags at half-staff on Sunday.

This was on all federal buildings nationwide.

Military liaison officers are helping families at hospitals.

The hospitals are in Edmonton, Calgary, Red Deer and Wainwright.

Mental health teams and chaplains are supporting soldiers and their families.