More than 15 people had to leave their homes after a fire broke out in a residential building early Monday morning.

The fire started around 3:30 a.m. in sheds behind the building on Desjardins Ave. in the Mercier–Hochelaga Maisonneuve borough.

The flames then spread to other sheds and to the main building. About 30 firefighters were called to the scene.

No one was hurt in the blaze.

Anumber of units were heavily damaged and firefighters say those units either did not have smoke detectors or they were not functional.

It is not yet known how the fire started.