The Calgary Fire Department says investigators are working to find out what caused a townhouse explosion in the city's southeast that injured four people.
Crews were called Thursday afternoon to the Mahogany neighbourhood and, while en route, they saw flames and a large plume of smoke from several blocks away.
When they arrived, they found the fully engulfed townhouse had collapsed, and the fire was spreading to neighbouring units.
Two firefighters and two people were hurt, with one taken to hospital with minor injuries.
The fire department says the house that exploded wasn't occupied but some of the adjacent ones were.
Anyone with photos or video of the explosion taken before firefighters arrived is asked to reach out to the fire department.