Witness VIDEO shows the upper walls collapsing as firefighters from Corunna, Owosso, Owosso Township, Perry, Durand, Vernon Township and Venice Township work to douse flames that had been shooting out of all the building's upstairs windows.

MORE VIDEO shows the building's devastated shell.

Shiawassee County 911 Repeater on Facebook reports power has been cut to city residents due to the fire and there is no word on when power will be restored.

A field fire in Perry is further occupying resources.

The Shiawassee County Sheriff's Office wrote on Facebook "Please be advised that Central Dispatch is extremely busy with 2 working fires and emergency calls currently. If you have an emergency please still call. If it is a non emergency please give us time to catch up. We appreciate your understanding."

State Representative Ben Frederick also commented on the situation in Corunna, saying "Pray for our first responders as they battle a fire at Cavalier Bar in Corunna and work to keep it from spreading to surrounding buildings. Please be respectful and give them space to do their jobs."

A message from Owosso Mayor Chris Eveleth reads "Thinking of Corunna this afternoon. Owosso has had more than its fair share of downtown fires, and we know first hand how devastating they can be. I sincerely hope everyone is ok, and if our neighbor to the east needs anything at all, we're here for you."

Firefighters remain on the scene of both incidents.