Authorities say fire crews in Detroit have responded to a string of about 16 building fires on the city's east side.
Arson was a possibility in the late Sunday and early Monday blazes. In one place, a fire burned several homes and a building formerly used as a church. The Detroit Free Press and The Detroit News report 16 fires were involved, and the cause of the fires was under investigation.
One firefighter was injured by a falling brick and was treated and released.
Authorities say the buildings involved mostly were vacant.
In addition, there were two fires in southwest Detroit and three cars set on fire.
Capt. Pat McNulty of the Detroit fire department's arson unit says a total of 21 fires is pretty high.