Three residential fires were reported about 80 minutes apart early Wednesday in Duluth, and arson has been confirmed in two of the blazes, authorities said.
"We now know that [two] were clearly and intentionally set fires," city spokeswoman Kate Van Daele said Wednesday afternoon. "There were accelerants at both locations."
At the same time, she said of the fires, "we are thinking they are not connected."
No injuries were reported in any of the fires, and no arrests have been made.
Firefighters responded to the first blaze about 12:10 a.m. at a vacant two-story house in the 200 block of Mesaba Avenue, where flames were seen on both levels.
The firefighters knocked down the blaze and made an initial damage estimate of $25,000.
Before that fire was under control, another one broke out around 12:35 a.m. nearly 5 miles to the south at the Memorial Park Apartments in the 600 block of N. Central Avenue. Fire officials said the fire was on a lower-level roof, and they did not believe it to be a case of arson.
Police officers fought the flames with fire extinguishers until firefighters arrived. Damage from this fire was assessed at $2,500.