The fire happened at around 5am yesterday in the Earls Court area of Alloa, Clackmannanshire.
Central Scotland Police have asked anyone with information to come forward. A spokesman said: "Three occupants were removed safe and well.
"However, damage was caused to the property as a result of the fire.
"It is being treated as a racially motivated incident and anyone with information should contact Central Scotland Police."
Meanwhile, a man was being treated in hospital after a fire in a flat.
He managed to escape the building in Caldwell Avenue, Glasgow.
Crews tackled the fire in the ground floor flat of a four-in-a-block building on Saturday morning.
The man was taken to Western Infirmary by ambulance.
Elsewhere, a blaze gutted a vacant laundrette and damaged two other neighbouring premises in Carnoustie, Angus, Tayside Fire and Rescue said.
The fire was reported shortly before 8pm yesterday.