MINNEAPOLIS — Thick smoke hovered over Minneapolis on Friday, hours after cheering protesters torched a police station that officers abandoned as a third night of violent protests flared over the death of George Floyd, a handcuffed black man who pleaded for air as a white police officer knelt on his neck.

Police evacuated the 3rd Precinct station, the focus of many of the protests, late Thursday to protect employees, a spokesman said. Livestream video showed protesters entering the building, where intentionally set fires activated smoke alarms and sprinklers. President Donald Trump threatened action, prompting a warning from Twitter for “glorifying violence.”

Dozens of fires were also set in nearby St. Paul, where nearly 200 businesses were damaged or looted. Protests spread across the U.S., fueled by outrage over Floyd’s death, and years of violence against African Americans at the hands of police. Demonstrators clashed with officers in New York and blocked traffic in Columbus, Ohio, and Denver.

Trump threatened to bring Minneapolis “under control,” calling the protesters “thugs” and tweeting that “when the looting starts, the shooting starts.” The tweet drew another warning from Twitter, which said the comment violated the platform’s rules, but the company did not remove it.

Trump also blasted the “total lack of leadership” in Minneapolis.

A visibly tired and frustrated Minneapolis Mayor Jacob Frey made his first public appearance of the night early Friday at City Hall and took responsibility for evacuating the precinct, saying it had become too dangerous for officers. As Frey continued, a reporter cut across loudly with a question: “What’s the plan here?”

“With regard to?” Frey responded. Then he added: “There is a lot of pain and anger right now in our city. I understand that … What we have seen over the past several hours and past couple of nights here in terms of looting is unacceptable.”

He defended the city’s lack of engagement with looters — only a handful of arrests across the first two nights of violence — and said, “We are doing absolutely everything that we can to keep the peace.” He said National Guard members were stationed in locations to help stem looting, including at banks, grocery stores and pharmacies.

The Minnesota State Patrol arrested a CNN television crew early Friday as the journalists reported on the unrest. While live on air, CNN reporter Omar Jimenez was handcuffed and led away. A producer and a photojournalist for CNN were also taken away in handcuffs.

The Minnesota State Patrol said the journalists were among four people arrested as troopers were “clearing the streets and restoring order,” and they were released after being confirmed to be media members. CNN said on Twitter that the arrests were “a clear violation of their First Amendment rights.”

Firefighters worked Friday to contain a number of blazes as National Guard troops blocked access to streets where businesses had been damaged. They marched side by side and block by block as they expanded a perimeter around a heavily damaged area.

Hundreds of Demonstrators Returned to the Minneapolis Neighborhood at the Center of the Violence

Protests first erupted Tuesday, a day after Floyd’s death in a confrontation with police captured on widely seen citizen video. In the footage, Floyd can be seen pleading as officer Derek Chauvin presses his knee against him. As minutes pass, Floyd slowly stops talking and moving.

Gov. Tim Walz activated the National Guard at the Minneapolis mayor’s request. The Guard tweeted minutes after the precinct burned that it had activated more than 500 soldiers across the metro area. A couple dozen Guard members, armed with assault-style rifles, blocked a street Friday morning near a Target store that has sustained heavy damage by looters.

The Guard said a “key objective” was to make sure firefighters could respond to calls, and said in a follow-up tweet that soldiers would assist the Minneapolis Fire Department. But no move was made to put out the 3rd Precinct fire. Assistant Fire Chief Bryan Tyner said fire crews could not safely respond to blazes at the precinct station and some surrounding buildings.

Earlier Thursday, dozens of businesses across the Twin Cities boarded up their windows and doors in an effort to prevent looting, with Minneapolis-based Target announcing it was temporarily closing two dozen area stores. Minneapolis shut down nearly its entire light-rail system and all bus service through Sunday out of safety concerns.

By Thursday night, hundreds of demonstrators returned to the Minneapolis neighborhood at the center of the violence. Demonstrators carried clothing mannequins from a looted Target and threw them onto a burning car.

Elsewhere in Minneapolis, thousands of peaceful demonstrators marched through the streets calling for justice. Local leaders repeatedly urged demonstrators to avoid violence.

“Please stay home. Please do not come here to protest. Please keep the focus on George Floyd, on advancing our movement and on preventing this from ever happening again,” tweeted St. Paul Mayor Melvin Carter, who is black.

Erika Atson, 20, was among thousands of people who gathered outside government offices in downtown Minneapolis, where organizers had called for a peaceful protest. Many protesters wore masks because of the coronavirus pandemic, but there were few attempts at social distancing.

Atson, who is black, described seeing her 14- and 11-year-old brothers tackled by Minneapolis police years ago because officers mistakenly presumed the boys had guns. She said she had been at “every single protest” since Floyd’s death and worried about raising children who could be vulnerable in police encounters.

“We don’t want to be here fighting against anyone. We don’t want anyone to be hurt. We don’t want to cause any damages,” she said. “We just want the police officer to be held accountable.”

The group marched peacefully for three hours before another confrontation with police broke out, though details were scarce.

After calling in the Guard on Thursday, Walz urged widespread changes in the wake of Floyd’s death.

“It is time to rebuild. Rebuild the city, rebuild our justice system and rebuild the relationship between law enforcement and those they’re charged to protect,” Walz said.

Among the casualties of the protests: a six-story building under construction that was to provide nearly 200 apartments of affordable housing.

Protesters Destroyed Property ‘Because the System Is Broken’

“We’re burning our own neighborhood,” said a distraught Deona Brown, a 24-year-old woman standing with a friend outside the precinct station, where a small group of protesters were shouting at a dozen or so stone-faced police officers in riot gear. “This is where we live, where we shop, and they destroyed it.”

“What that cop did was wrong, but I’m scared now,” Brown said.

Others in the crowd saw something different in the wreckage.

Protesters destroyed property “because the system is broken,” said a young man who identified himself only by his nickname, Cash, and who said he had been in the streets during the violence. He dismissed the idea that the destruction would hurt residents of the largely black neighborhood.

“They’re making money off of us,” he said angrily of the owners of the destroyed stores. He laughed when asked if he had joined in the looting or violence. “I didn’t break anything.”

In New York City, protesters defied New York’s coronavirus prohibition on public gatherings Thursday, clashing with police, while demonstrators blocked traffic in downtown Denver and downtown Columbus. A day earlier, demonstrators had taken to the streets in Los Angeles and Memphis.

In Louisville, Kentucky, police confirmed that at least seven people had been shot Thursday night as protesters demanded justice for Breonna Taylor, a black woman who was fatally shot by police in her home in March.

Anger over the killing extended to Africa, where the head of the African Union Commission on Friday rejected “continuing discriminatory practices against black citizens of the USA.” In a series of tweets, Moussa Faki Mahamat urged the “total elimination” of all forms of racism in the U.S.

In Mississippi, the mayor of the community of Petal resisted calls to resign following his remarks about Floyd’s death. Hal Marx, a Republican, asked on Twitter: “Why in the world would anyone choose to become a police officer in our society today?” In a follow-up tweet, he said he “didn’t see anything unreasonable.”

The city on Thursday released a transcript of the 911 call that brought police to the grocery store where Floyd was arrested. The caller described someone paying with a counterfeit bill, with workers rushing outside to find the man sitting on a van. The caller described the man as “awfully drunk” and said he was “not in control of himself.”

Asked by the 911 operator whether the man was “under the influence of something,” the caller said: “Something like that, yes. He is not acting right.” Police said Floyd matched the caller’s description of the suspect.

State and federal authorities are investigating Floyd’s death.

Chauvin, the officer who knelt on Floyd’s neck, was fired Tuesday, along with three other officers involved in the arrest.