The Ontario Fire Marshal's office is investigating the cause of an early morning fire at an apartment building on Walnut St.
District Chief Andrew Britton says fire crews were called about the blaze around 3:30am Sunday. The fire broke out at an apartment unit located on the 14th floor.
London police say three residents and one firefighter was taken to hospital.
The extent of their injuries is unknown, however, it's believed the reason the firefighter was sent to hospital was not directly related to the actual fire.
Britton says the flames were visible from the street but the fire was contained to the one apartment unit.
