The flames of a fire that engulfed a group of buildings on Simpson Street, centred on the old Underground Gym location near Hardisty Street, have now been extinguished.

Thunder Bay police have closed Simpson Street from Ogden Street to the East End Bridge while Thunder Bay Fire Rescue investigates the cause of the blaze, which is still unknown.

Several businesses in the surrounding area have closed today in response to the fire.

This is an ongoing story, and may be updated as more information comes to light.