An overnight fire forced about 200 people from their homes on Montreal's South Shore early Wednesday morning.

The fire started around 2:45 a.m. in a electrical room linking two neighbouring apartment buildings in Longueuil. The cause of the fire is not yet known, according to police.

Smoke infiltrated several floors of the two apartment buildings on de la Lousiane Street, close to the intersection of Taschereau Boulevard and Route 132.

Firefighters were quickly able to put out the fire.

While those who had to leave their homes were sheltered in buses, residents living on the top floors of the buildings were confined to their units.

No one was injured. Residents were able to return to their apartments around 5 a.m.

An investigation is underway.

With files from Radio-Canada and la Presse Canadienne