Firefighters continue to battle a three-alarm blaze that broke out Thursday evening at a two-storey building in Ottawa's Vanier neighbourhood.

An employee at 81 Montreal Rd. called 911 at around 6:40 p.m. to report "haze" coming from the inside of the building, said Ottawa Fire Services in a media release.

The building houses a pawn shop and appliance store on the ground floor and a church on the second floor.

It was initially declared a two-alarm fire, but a third alarm was called in around 9 p.m. when the building began to show signs of collapsing, fire officials said.

It was also around that time firefighters had to retreat from the building.

No injuries have been reported.

As of 10:20 p.m., firefighters were still fighting to keep the fire from spreading to surrounding buildings.

Heavy equipment has been called in to assist with the building's eventual demolition, officials said, and a fire investigator is on scene to determine the cause of the blaze.

Police have closed off Montreal Road between North River Road and the Vanier Parkway and are urging people to avoid the area.