Protesters took to the streets for a sixth night Sunday, as anger over the Memorial Day death of a black man in police custody burned across a country already reeling from the deadly coronavirus and the resulting economic crisis.

As the violent and chaotic weekend drew to a close, officials in more than two dozen cities had imposed sweeping curfews, including in Minneapolis and St. Paul, the epicenter of the crisis. Governors in 26 states called in the National Guard. And Secret Service agents clashed for a second day with demonstrators outside the White House, where President Trump used social media to assail Democrats and threaten protesters.

At least six people were killed in violence that flared as demonstrations in parts of the country devolved into mayhem. Gunfire rang out from Detroit to Indianapolis to Chicago to Omaha — places where authorities said people were slain in shootings connected to the protests. But there were also scenes of peaceful assembly, as well as of police officers kneeling in solidarity and protesters placing themselves before store fronts to prevent looting and brawling at odds with the message of nonviolence.

By Sunday evening, police had arrested 2,564 people in two dozen cities over the weekend, according to a tally by The Washington Post.

The events put the country at a precipice. And the question, as May turned to June, was whether the events of the weekend — which saw police escalate their tactics against protesters as parts of cities were set ablaze — would mark the climax of the unrest, or its onset.

“We’re at a crossroads,” said Melina Abdullah, a co-founder of the Los Angeles chapter of Black Lives Matter and a professor at California State University at Los Angeles. “Either the existing system of repressive and brutal policing is going to continue to assert itself, and the powers that be will sign off on it, or they will get the message that the people are sending, that we cannot continue with this form of policing in this country.”

Democrats on May 31 criticized the White House response to nationwide protests over policing and called for new policies to govern police departments. (The Washington Post)

She added: “People are going to have to figure out what side they stand on. Black people — we’re fed up. And there’s really very little to lose at this point.”

That sentiment was echoed in dozens of cities across the country, as authorities strained to respond to the eruption of protests over the death of 46-year-old George Floyd.

In Philadelphia, where retail stores were ordered closed and the Center City area was locked down after widespread looting, protesters returned to the streets Sunday to march toward City Hall. Wilmer Wilson IV, draped in a white sheet spray-painted with the words “what is justice,” joined hundreds of peaceful protesters in defying the city’s stay-at-home order, designed to slow the spread of the novel coronavirus, because of “the continuing state of disaster that is unfolding across the country and across black bodies.”

“As long as people are coming out, I’ll be here,” the 30-year-old artist vowed.

But authorities promised to step up their presence as well, as officers clad in riot gear used rubber bullets, pepper pellets and tear gas to quell uprisings, sometimes firing at bystanders and journalists. In Minneapolis, a driver who barreled his tanker truck toward protesters filling the city’s I-35 highway was arrested Sunday evening.

In addition to the mobilization of National Guard units, Mark Morgan, the acting commissioner of U.S. Customs and Border Protection, said Sunday his agency was deploying “officers, agents and aviation assets across the country.” The nation’s top law enforcement official, Attorney General William P. Barr, echoed Trump in blaming “far-left extremist groups” while furnishing no evidence about the cause of the violence.

The president, meanwhile, launched a series of tweets pressing for a severe crackdown and ridiculing Democratic mayors and governors. He shared posts calling for “overwhelming force” and amplified an account devoted to the QAnon conspiracy theory, writing, “STRENGTH!” On Friday, he was taken by Secret Service agents to an underground bunker at the White House, according to two officials familiar with the incident, as the president’s residence became a target of protests that convulsed the city throughout the weekend.

The president also declared that the United States “will be designating” the far-left anti-fascist movement known as antifa “as a Terrorist Organization,” even though he has no apparent legal authority to apply such a label to a domestic group. The name describes a loose collective or a left-wing political mind-set, some of whose adherents favor aggressive tactics, rather than identifying a well-organized group.

“The intention is to find the boogeyman,” said Adam Klein, a professor of communication studies at Pace University who has studied the movement’s confrontation with far-right activists in the lead-up to the 2017 “Unite the Right” rally in Charlottesville.

As questions mounted about whether extremists of various stripes were infiltrating the protests, Klein said there was still too little evidence to point to outside forces.

“It’s not that we shouldn’t hold culprits accountable for being violent, but it takes away from the reasons people are protesting,” he said. “It’s like a conspiracy theory to me, used to change the subject.”

Protesters were joined by some elected officials in seeking to keep the focus on police violence against black Americans.

“We’ve often used the word ‘unprecedented’ in 2020, from the pandemic to the state of our economy, but police officers killing black people is unfortunately the one thing that’s not unique,” Melvin Carter, the black mayor of St. Paul, Minn., said in an interview.

The four police officers involved in the fatal Memorial Day encounter in Minneapolis were fired last week, and Derek Chauvin, the officer who pressed his knee into Floyd’s neck for more than eight minutes, has been charged with third-degree murder. Minnesota Gov. Tim Walz (D) said Sunday the state’s attorney general, Democrat Keith Ellison, would take the lead on the high-profile case.

Video of the May 25 arrest captured by a bystander showed Floyd, who was handcuffed, repeatedly telling officers, “I cannot breathe.” The cry is again echoing across the country, and around the world.

Hundreds of demonstrators in London rallied, with some chanting “no justice, no peace” in solidarity with the American-born movement against racial bias in the criminal justice system. The London protests took place in defiance of rules against large gatherings due to the coronavirus pandemic.

Demonstrators also took to the streets in Berlin and Toronto.

But the sharpest questions were asked domestically. New York Mayor Bill de Blasio (D) launched an investigation after city police officers on Saturday appeared to drive two vehicles into a throng of protesters, though he also said he would not “blame” the officers involved. A similar scene was filmed on Sunday in Los Angeles, where a police vehicle rammed into a crowd of people.

Meanwhile, Atlanta Mayor Keisha Lance Bottoms said Sunday two police officers had been fired for using excessive force over the weekend. While some called on Trump to address the nation, Bottoms, who has emerged as a leading voice of calm during the uprisings, said she feared the effect of the president’s remarks.

“He should just stop talking,” the Democrat said on CNN’s “State of the Union.” “This is like Charlottesville all over again. . . . I wish that he would just be quiet. Or if he can’t be silent, if there is somebody of good sense and good conscience in the White House, put him in front of a teleprompter and pray that he reads it and at least says the right things, because he is making it worse.”

After the 2017 white-supremacist rally in Charlottesville, Trump observed that there were “very fine people on both sides.” In recent days, he has responded to the protests across the country by condemning the demonstrators as “THUGS,” urging authorities to “get tougher” and predicting that “when the looting starts, the shooting starts.”

More local curfews were simultaneously in place across the country than at any time since 1968, following the assassination of Martin Luther King Jr. In Louisville, where protesters have issued newly urgent condemnations of the March shooting of Breonna Taylor by city police officers, Mayor Greg Fischer instituted a 9 p.m. curfew Saturday that was also in effect Sunday evening. Officials in Chicago on Sunday announced reduced access to the city’s downtown, which is open only to essential employees and people who live in the area, and a citywide curfew was set from 9 p.m. Sunday evening until 6 a.m. Monday.

But the regulations were disregarded from Detroit to Miami-Dade, where hundreds refused to disperse in the Biscayne Boulevard Historic District. As police moved in, a small crowd hurled heavy objects at a glass CVS storefront. Some tried to discourage the vandalism to no avail, as a police officer lobbed a flash bang into the roadway.

As thousands of National Guard troops were activated in 26 states and the District, another 2,000 Guard soldiers and airmen were standing by for possible activation, the Guard Bureau said in a statement.

“The situation is fluid so those numbers can change rapidly,” the statement said.

Nearly a fifth of the country’s more than 2,500 arrests were in Los Angeles, where protesters clashed with police, causing city officials to ask the state for 500 to 700 National Guard troops overnight Saturday as Los Angeles ordered a curfew.

In New York City, 345 people were arrested Saturday evening and early Sunday morning, police told The Post, bringing the total number of arrests in the city over the weekend to nearly 600. Police were unable to provide a breakdown of the charges against those arrested. Forty-seven police cars were damaged and 33 officers were injured Saturday, police said.

While many of the demonstrations were peaceful, the scenes of violence, destruction and looting at some of Saturday’s protests prompted calls for restraint.

Presumptive Democratic nominee Joe Biden released a statement early Sunday acknowledging the pain that has inspired the widespread protests and urging those feeling it to avoid violence.

“Protesting such brutality is right and necessary. It’s an utterly American response,” said Biden, who on Sunday visited the site of the weekend’s protests in Wilmington, Del. “But burning down communities and needless destruction is not.”

Trump national security adviser Robert C. O’Brien, meanwhile, denied that systemic racism is an issue in U.S. law enforcement.

“I don’t think there’s systemic racism,” O’Brien said on CNN. “I think 99.9 percent of our law enforcement officers are great Americans, and many [are] African American, Hispanic, Asian.”

With the protests over Floyd’s death showing little sign of abating, former and current government officials warned that the mass demonstrations could lead to new waves of coronavirus infections.

“There’s going to be a lot of issues coming out of what’s happened in the last week, but one of them is going to be that chains of transmission will have become lit from these gatherings,” former Food and Drug Administration commissioner Scott Gottlieb said in an interview on CBS News’s “Face the Nation.”

To some protesters, however, the risk was worth taking, even as it compounded the danger of the chaotic events. In Houston, Chavon Allen, 33, agonized over whether it was a good idea to bring her 8-year-old daughter to an unpredictable protest in the streets of downtown. Ultimately, she decided the viral menace paled in comparison to another threat to her health and safety.

“I understand we’re in a global pandemic right now, but I also feel like our lives are in a state of emergency as well because of the police,” she said, noting her brother had been shot by a Houston police officer three years earlier and survived. “That’s why we’re out here.”

William Booth in London, Peter Holley in Houston, Scott Wilson in Los Angeles, Maura Ewing in Philadelphia, Michael Majchrowicz in Miami-Dade County, Eva Dou in Detroit, and Meryl Kornfield, Seung Min Kim, Josh Dawsey, Jacqueline Alemany, Hannah Knowles and Missy Ryan in Washington contributed to this report.