The Winnipeg Fire Paramedic Service's arson unit was dispatched after fire broke out in the old Merchants Hotel shortly after 9:30 p.m. Friday night.
Firefighters said when crews arrived on scene, smoke and flames were showing from the building.
Fires were located on first, second and third floors.
Crews said they had to force their way into the front and side doors to help get the fire under control.
The building was searched and no one was located in inside.
Crews said the building was ventilated and returned to normal.
No one was hurt.
A damage estimate wasn't available Saturday, firefighters said.
Crews said the fire department's arson unit was dispatched following the fire, and the cause remains under investigation.
MERCHANTS HOTEL UNDER REDEVELOPMENT
The University of Winnipeg and the North End Community Renewal Corporation, along with the provincial government, have been working to convert the old hotel in to a mix of university classrooms, affordable student housing and retail shops.
The hotel closed in 2011 when the province bought it. The hotel, which was built in 1904, had become infamous in the neighbourhood.
The redevelopment of the site is anchored a wing of the U of W’s Urban and Inner-City Studies department.
MINIMAL DAMAGE CAUSED
Merchants Corner Incorporated is overseeing the development of the old hotel into an education and community space.
Dawn Sands is with The North End Renewal Corporation, which is helping with the administration of the project and sits on the board of MIC.
Sands said damage is minimal and renovations will continue.
Timelines of the project will not be affected.
With files from Cameron MacLean
