OTTAWA -- No one was hurt in a late afternoon fire in Ottawa's ByWard Market.

Ottawa Fire says it received multiple 911 calls reporting a large amount of black smoke coming from the roof of a building near the intersection of Clarence and Dalhousie streets around 5:35 p.m.

When firefighters arrived on scene, they discovered the fire was coming from the rear of a two-storey duplex at 140 Clarence Street.

Firefighters quickly began a fire attack from the outside on the balcony that was on fire before entering the building to check for occupants and extensions. A fire official on scene reported the fire was in the walls and roof area at the rear of the building. 

The structure was unoccupied at the time of the fire.

Investigators are searching for the cause of the fire.