Police in Ottawa are investigating the possibility that someone deliberately started a fire on the ground floor of an all-female rooming house on Nepean Street.

There are reports that a Molotov cocktail was lobbed into the three-storey building late Saturday, but officials say the cause of the blaze has not been confirmed.

The fire was contained to one unit. Damage is estimated to be about $100,000.

About 20 women had to flee the building, but no one was injured.