Several homes and businesses were nothing more than smoldering rubble as firefighters continued dousing hot spots.
At least 16 structures were on fire early Thursday, the Minneapolis Fire Department, citing 911 logs, told NBC affiliate KARE.
Much of the violence Wednesday night broke out along East Lake Street as Mayor Jacob Frey pleaded for peace.
"Please, Minneapolis, we cannot let tragedy beget more tragedy," Frey said in a statement Thursday morning. "The area along Lake has become unsafe. We are asking for your help in keeping the peace tonight."
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Four Minneapolis police officers were fired after one of them was shown on camera putting his knee on the neck of Floyd, a black man who was in handcuffs, for about eight minutes Monday. Floyd, whom police approached while responding to a call about a forgery at a nearby store, was recorded pleading with Officer Derek Chauvin, "Please, please, please, I can't breathe."
NBC News' attempts to obtain comment from the officers or their attorneys have been unsuccessful.
The Police Officers Federation of Minneapolis said in a statement that it was not the time to rush to judgment and that the officers were fully cooperating in the investigation.
"We must review all video. We must wait for the medical examiner's report," the statement said. "Officers' actions and training protocol will be carefully examined after the officers have provided their statements."
Floyd's death is being investigated by the FBI and the Minnesota Bureau of Criminal Apprehension.