A fire engulfed the Soo Line bridge over the Leech Lake River on Wednesday, heavily damaging the bridge and forcing its closure.

The fire was reported at 1 a.m. at the bridge in Federal Dam, a city of 106 residents in Cass County, about 220 miles northwest of the Twin Cities.

The bridge was “significantly” damaged, according to Cass County Sheriff Tom Burch, and will remain closed until further notice. The incident is under investigation.