CLEVELAND, Tenn. (AP) — Authorities say the inside of a Tennessee courthouse caught fire and sustained substantial damage.

Bradley County Sheriff Office spokesman James E. Bradford Jr. says a bystander saw black smoke coming from inside the county courthouse in downtown Cleveland, Tennessee on Saturday morning.

Bradford says the Cleveland Fire Department firefighters forced their way into the building and found the fire originated from a first-floor mechanical room.

Bradford says the interior of the courthouse has sustained substantial smoke and fire damage.