The cause of a fire at a multi-unit apartment building in downtown Fredericton is under investigation.

Acting Platoon Captain John Dunbar says crews were called to the building on Brunswick Street, between York and Westmorland streets, around 5 p.m. Saturday.

Dunbar says the fire, which was contained to one apartment in the rear of the main floor, was quickly knocked down.

He says there was significant damage to the apartment, while the rest of the building sustained smoke damage.

No one was injured.