A three-alarm fire at a Mississauga office complex led to some scary moments for its occupants and resulted in at least one person being treated for minor smoke inhalation.

The call came in to Mississauga Fire at 4:37 p.m. on Wednesday.

The flames broke out on the building's third floor at the Erindale Corporate Centre, located at 1270 Central Parkway West. It is very close to the Erindale GO Transit station.

One occupant said the fire alarms went off and his floor started filling with smoke. When they went to the stairwell, they found it to be filled with smoke, so his office congregated on the fifth floor. Others described a scene of fear, with some wondering how they would make it out to safety.

Smoke could be seen gushing out of a window at one point. There were some reports the smoke filled stairwells, trapping people in their offices.

Police advised occupants of the building to follow the instructions given them by 911 operators.  TV images later showed people being led out of the building and into a waiting city bus.

An air ambulance had been dispatched to the scene as a precaution, but its services ultimately weren't required.

By about 8 p.m., most of the firefighting vehicles and firefighters had left the scene.

Officials with Mississauga Fire told reporters at the scene they considered the fire suspicious simply because they have no idea at this point why it occurred. The Ontario Fire Marshal's Office will be brought in to investigate.

However, there are suggestions the fire may have started outside the third-floor constituency office of Conservative MP Bob Dechert, who represents the Mississauga-Erindale riding. There was a knock on the door, and when staff opened it, they reportedly saw the fire burning.

Efforts to control it with a fire extinguisher were unsuccessful, CTV Toronto reported.

With a report from CTV Toronto's Michelle Dube