Firefighters are currently battling blazes that have affected multiple homes in East Gwillimbury.
York Region Police say that between eight and 10 houses, near Mount Albert Road and Ninth Line, are on fire.
At least four homes have already burned to the ground, Stouffville Fire Services say.
Aerial photographs showed thick smoke billowing from rooftops in the area.
No injuries have been reported.
The cause of the fires was not immediately known, but police say it is suspicious.
