MINNEAPOLIS — The protests started peacefully Tuesday night, as hundreds marched to the 3rd Precinct police headquarters to demand accountability for the officer who jammed his knee into George Floyd's neck for more than eight minutes as he gasped for breath.

Tensions quickly escalated. By the second night, people had looted nearby businesses and set them on fire.

By the third night of protests, the police precinct was also on fire. By the fourth, dozens of buildings were set ablaze, and anger once directed just at the police exploded into all-out mayhem.

This Midwestern city is now consumed by fear and unease triggered by the anarchy playing out after dark in certain neighborhoods — and worries that the violence could quickly spread throughout the city. Some residents now stand guard outside their homes with clubs and guns to fend off opportunists or possible arsonists; others have contemplated fleeing the city for the weekend.

Video from several U.S. cities showed police using force against protesters and bystanders on May 30 during a night of protests over George Floyd's death. (The Washington Post)

Minnesota Gov. Tim Walz (D) has said that the protest has been hijacked by outside extremist groups, and theories of which ones are circulating through neighborhoods and online.

When former NBA player Royce White organized a Friday afternoon demonstration in Minneapolis that ultimately led to thousands peacefully kneeling on Interstate 35, he notified people by text message to avoid infiltration by agitators unsympathetic to the cause.

“We didn’t want a Facebook event,” said White, a Minnesota native. “We didn’t want people coming and trying to do something dangerous or violent. We have successfully proved that we can protest in peace, despite all the stories that are shown on the news.”

Chaos ensued across the country on the evening of May 29 as protesters in various cities demonstrated in relation to George Floyd’s death. (The Washington Post)

Since Floyd’s death Monday, protests have popped up in dozens of cities across the country to call for an end to police officers killing people of color and an end to the nation’s racial inequities, which have been made glaringly clear by the disparate effects of the covid-19 crisis and mass unemployment.

As the frustration exploded this week, a unifying refrain has been chanted nationwide: “No justice. No peace.”

Those words could be heard in Philadelphia and Houston, Los Angeles and New York City, Phoenix and Columbia, S.C. They were scrawled in black letters on an orange barricade in Cincinnati and written on a poster held up outside the Kansas statehouse. Outside the Detroit police headquarters, activists added one more line: “No racist police.”

Eight years after demonstrators took to the streets to protest the death of 17-year-old Trayvon Martin, sparking the Black Lives Matter movement, there’s exasperation that people of color continue to die during encounters with police officers. That little seems to change. That little has grabbed the attention of elected leaders.

“The police have no accountability,” said Juan Peralta, 26, who marched along East Lake Street in Minneapolis on Friday night, carrying a megaphone and leading chants of Floyd’s name. “This is our anger speak. This is the way we talk because we’re not listened to. We’re acting up because we’re tired. We’ve been tired.”

Cassy Craine, who attended a protest in downtown Minneapolis on Thursday and was hit repeatedly by pepper-spray-like irritants released by police, added: “For generations our voices have not been heard. We need more people of color policing, and policing their own neighborhoods.”

Horatio Gonzalez, 22, and Xitlalic Rosa, 23, traveled from Indiana to Chicago’s Federal Plaza on Saturday to attend their first protest. Outside the Trump International Hotel and Tower Chicago, a thick crowd of people surrounded a black SUV and destroyed it by hitting it with blunt objects, smashing the glass, opening the doors and ruining everything inside. Police in riot gear pressed the crowd back with batons.

“I’m fed up,” Gonzalez said. “It’s time.”

“Ever since Trump came into office, the violence against black people is glorified,” Rosa said. “He makes it seem like it’s okay.”

Two-and-a-half months before Floyd’s death, 26-year-old Breonna Taylor was shot to death in her apartment in Louisville after three police officers entered while serving a “no-knock warrant.” In late February, 25-year-old Ahmaud Arbery was shot and killed by two vigilantes while he was jogging in South Georgia.

Some protesters have said that deaths and tragedies are not enough to force America to wake up, to pay attention to what is happening and has been happening for years — that sometimes it takes fire and shattered windows and chaos. To some, that’s what “no peace” has to look like until there is justice.

“It wasn’t a Negro spiritual that got my people out of chains. It was war,” Tay Anderson, a Denver Public School Board member in his 20s, yelled into a megaphone at a rally in Denver on Friday evening. “Now that we have your attention and your cities are burning to the ground, let me hear you say, ‘Black lives matter.’ ”

There are worries that protesters could loot or destroy businesses at the Midtown Global Market, and a crew of volunteers gathered there Saturday to clean up after Friday night’s destruction. Ming-Jinn Tong, a pastor at Bethlehem Baptist Church in Minneapolis, started a group called Support The Cities to help community members “wipe the tears of our city as our city weeps together.”

“We have been watching our city first suffer from watching the unjust murder of George Floyd,” he said. “We also watched as our city began to burn. The riot we’re seeing in the street, is it not the riot that is in the hearts of people that have been oppressed for so long and is becoming visible?”

Tamika Mallory, an activist based in New York City, traveled to Minneapolis this week and gave a passionate speech at a news conference, accusing instigators of infiltrating protests.

“You are paying instigators to be among our people out there, throwing rocks, breaking windows and burning down buildings,” Mallory said in a speech that has widely circulated on social media. “And so young people are responding to that. They’re enraged, and there’s an easy way to stop it: Arrest the cops. Charge the cops. Not just some of the cops, all of the cops. Not just here in Minneapolis. Charge them in every city across America where our people are being murdered. Charge them everywhere.”

She expressed outrage at some people being more offended by stores being looted than people being killed: “I don’t give a d--- if they burn down Target because Target should be on the streets with us calling for the justice that our people deserve,” she said.

Thousands of people — mostly white — gathered in South Minneapolis’s Powderhorn Park on Saturday afternoon to discuss ways to keep their community safe amid an outbreak of fires, especially the diverse neighborhoods on the South Side. The neighborhood is known for its funky, hippie vibe, with vegan restaurants and more puppeteers per capita than anywhere else in the state.

In previous days, many had joined peaceful protests, creating signs expressing solidarity with their black neighbors and marching along major streets. But now that the movement seems to have been hijacked and transformed into something destructive and sinister, they tried to figure out how to pivot.

“I personally have seen middle-aged white guys in groups wearing identical clothes, tactical clothing and masks, working in concerted effort,” said Sam Gould, a writer, artist, activist and book maker who lives blocks from the park and helped lead the meeting. “It is a strategy to incite chaos.”

The activists heard from Alondra Cano, a city council member who represents the Ninth Ward, the most diverse in the city, with large American Indian and Latino populations.

“I want to relay to you the requests and the pain and the fear that I am feeling from immigrant people on Lake Street who oftentimes don’t have the ability or the privilege to participate in some of these spaces,” said Cano, herself an immigrant. “They are requesting more protection. They are requesting that we prevent more people from burning buildings down on Lake Street, as those buildings represent the blood, sweat and tears that they have invested in turning Lake Street around.”

As Cano talked about the importance of keeping the neighborhood safe, an African American woman who is a local jazz singer interrupted.

“I am not going to stand here and say the fires weren’t necessary,” said the woman, who spoke on the condition of anonymity for fear of being harmed. “The fires were deeply necessary.”

Johnson reported from Washington. Tarkor Zehn in Minneapolis, Shayna Jacobs in New York City, Eva Dou in Detroit, Mark Guarino in Chicago, Jennifer Oldham in Denver, Michelle Boorstein in Washington and Adina Solomon in Atlanta contributed to this report.