"Please,please,Minneapolis,"an emotional Mayor Jacob Frey told aStar Tribune reporter just before midnight."We cannot let tragedy beget more tragedy. The activity around Lake and Hiawatha is now unsafe. Please,help us keep the peace..."
The violence followed a day-long protest outside the Third Precinct police headquarters,where officers sought to disperse crowds with flash-bang grenades,tear gas and projectiles through the day and night.
Demonstrators pelted police with rocks,water bottles and other projectiles.
Television news footage from a helicopter flying over the area showed dozens of individuals looting a Target store,running out with armloads of clothing and shopping carts filled with merchandise.
Earlier,Frey called on prosecutors to file criminal charges against the police officer who was shown kneeling on Floyd's neck.
"I've wrestled with,more than anything else over the last 36 hours,one fundamental question:Why is the man who killed George Floyd not in jail?"Frey said."If you had done it,or I had done it,we would be behind bars right now. And I cannot come up with a good answer to that."
The officer,along with three others involved in arresting Floyd,were dismissed from the police department as the FBI on Tuesday opened an investigation into the incident.
The city identified the four officers on Wednesday as Derek Chauvin,Thomas Lane,Tou Thao and J Alexander Kueng. It did not identify the officer who had his knee against Floyd's throat,and provided no further information.
In addition to the protests near the Third Precinct in Minneapolis,demonstrators also gathered Wednesday at the homes of Hennepin County Attorney Mike Freeman and the Oakdale home of Chauvin.
"Why is the man who killed George Floyd not in jail? If you had done it or I had done it we would be behind bars right now,"Frey told a news briefing on Wednesday."I am calling on Hennepin County Attorney Mike Freeman ... to charge the arresting officer in this case."
Frey did not specify what charge he thought was appropriate for the officer,but said he had relayed his wish to Freeman,the prosecutor in the county where Minneapolis is located.
On Tuesday,the Hennepin County Attorney's Office said it would make a charging decision after the state's Bureau of Criminal Apprehension and the Federal Bureau of Investigation concluded their investigations.
The Police Officers Federation of Minneapolis,the union that represents the city's police force,said in a statement the officers involved were co-operating with investigators and it was"not time to rush to judgment".
"We must review all video. We must wait for the medical examiner's report,"the union said,asking the community to remain calm.
US President Donald Trump said on Twitter he wanted an FBI investigation"to be expedited",saying he appreciated"all the work done by local law enforcement".
"My heart goes out to George's family and friends. Justice will be served!"he tweeted.
The case is reminiscent of the 2014 killing of Eric Garner,an unarmed black man in New York City who died after being put in a police chokehold and telling officers,"I can't breathe."The officer who placed Garner in a fatal chokehold was fired but not criminally prosecuted.
The Garner case was one of a series of killings of black men by US police officers that fuelled the"Black Lives Matter"movement,which campaigns against violence towards black people and systemic racism.
A protest in Minneapolis was planned for Wednesday in front of the home of a police officer organisers say was involved in the incident,according to a posting on Facebook.
The organiser said a peaceful protest was planned,but the officer will"feel our pain and what it's like to be afraid for his life".
Reuters,Star Tribune (Minneapolis)