Fire officials are investigating a three-alarm fire that ripped through a Manassas self-storage facility overnight, damaging at least 85 units.

The fire broke out in a building in the 7900 block of Sudley Road around 11 p.m. Sunday. About 140 firefighters were called to battle the blaze.

Investigators believe the fire started inside the building and spread to scores of storage units once the roof caught fire. About 85 units and their contents are believed to have been completely destroyed.

Officials said the flames have been extinguished but the contents of some of the units are still believed to be smoking.

Due to damage to the roof, the unstable building has been condemned and firefighters cannot enter.

The cause of the fire remains under investigation.