Montreal police are investigating a suspicious fire downtown that drew 60 firefighters to the scene.

It broke out around 4 a.m. inside a commercial building at 858 St. Catherine St. east.

The fire began in a bar on the second floor of the three-storey building.

A worker inside the building reported hearing a blast before he saw flames and called 911.

There was extensive damage to the bar, which was under renovation.

The concrete structure helped to limit the damage to the second floor and firefighters were able to put it out quickly.

There were no injuries.