Canada mourns after at least four are killed and dozens injured in an explosion and fire at an Alberta army base

Prime Minister Mark Carney called the 'violent, fast-moving' blaze one of the worst peacetime tragedies for Canada's armed forces on Canadian soil. He said the nation is in 'mourning'. The disaster struck at a military base in Wainwright, Alberta, where an explosion preceded the fire.

Some reports put the death toll at seven.