The protesters raged through the night, invoking the name of George Floyd, a black man who died after a white police officer knelt on his neck for several minutes even after Floyd stopped moving and pleading for air.

Some held up signs with Floyd's last words: “I can't breathe." Graffiti on city walls called police murderers. In a highly symbolic image, a protester carried a U.S. flag upside down, a sign of distress.

Among Thursday night's casualties was a Minneapolis police station that demonstrators torched after the department abandoned it. Some protesters doused their faces with milk after being exposed to tear gas from police. Others set off fireworks as fires burned in the background. Looting was rampant.

Authorities move through an area filled with tear gas Thursday, May 28, 2020, in St. Paul, Minn. Protests over the death of George Floyd, a black man who died in police custody, broke out in Minneapolis for a third straight night. (AP PhotoJohn Minchillo)

Authorities move through an area filled with tear gas Thursday, May 28, 2020, in St. Paul, Minn. Protests over the death of George Floyd, a black man who died in police custody, broke out in Minneapolis for a third straight night. (AP PhotoJohn Minchillo)

It was the third night of violent protests after Floyd died in a confrontation with officers outside a grocery store.

Fires continued to burn Friday morning in Minneapolis and nearby St. Paul, and National Guard members were being stationed in locations to help stem looting.

Under fire from President Donald Trump, who criticized the city's mostly hands-off approach with protesters, Minneapolis Mayor Jacob Frey defended the policy and said it was his decision to evacuate the police precinct because officers were at risk.

Protestors demonstrate outside of a burning Minneapolis 3rd Police Precinct, Thursday, May 28, 2020, in Minneapolis. Protests over the death of George Floyd, a black man who died in police custody Monday, broke out in Minneapolis for a third straight night. (AP PhotoJohn Minchillo)

Protestors demonstrate outside of a burning Minneapolis 3rd Police Precinct, Thursday, May 28, 2020, in Minneapolis. Protests over the death of George Floyd, a black man who died in police custody Monday, broke out in Minneapolis for a third straight night. (AP PhotoJohn Minchillo)

 Young men stand atop a burning car in the Target parking lot E. Lake St. during a third night of unrest following the death of George Floyd while in Minneapolis police custody early in the week and seen Thursday, May 28, 2020, in Minneapolis, MN.] DAVID JOLES • david.joles@startribune.com Folo on death of George Floyd at hands of Minneapolis police.**Edward Washington,cqStar Tribune via AP)

Young men stand atop a burning car in the Target parking lot E. Lake St. during a third night of unrest following the death of George Floyd while in Minneapolis police custody early in the week and seen Thursday, May 28, 2020, in Minneapolis, MN.] DAVID JOLES • david.joles@startribune.com Folo on death of George Floyd at hands of Minneapolis police.**Edward Washington,cqStar Tribune via AP)