The Trump administration on Sunday intensified its effort to pin blame on the far-left “antifa” movement for violent demonstrations over police killings of black people, as the president vowed on Twitter to designate antifa a terrorist organization and Attorney General William P. Barr asserted that it and other groups’ activities constituted “domestic terrorism.”

Trump cannot, for practical and legal reasons, formally designate antifa a terrorist organization, and neither he nor his attorney general has made public specific evidence that the far-left movement is orchestrating the fiery protests that have erupted in dozens of U.S. cities.

In Minnesota, where the unrest began after 46-year-old George Floyd died after police officer Derek Chauvin knelt on his neck for more than eight minutes, officials have alleged the violence was fueled by different external forces, including white supremacists and drug cartels. They, too, have not offered detailed evidence to support those claims.

Chauvin has been charged with third-degree murder and second-degree manslaughter.

Protests — especially those of the scale seen in the United States in recent days — are complicated affairs, often drawing participants with a range of political ideologies and motivations, including some with bad intentions. But some observers said they see in Trump’s targeting of antifa an attempt to shift focus away from what sparked the demonstrations: outrage over killings of black people by police.

“The idea of antifa ‘masterminding’ what’s happening over the last few days — if you know anything about the subject — is ludicrous,” said Mark Bray, a historian and author of the 2017 book “Antifa: The Anti-Fascist Handbook.” “There’s a real investment on the part of the administration and their allies in portraying these recent protests as organized from the top down, and not a spontaneous outpouring of rage.”

At nightfall in Minneapolis, a dichotomy between the violent and the nonviolent often emerges, with brief arguments ensuing at the appearance of shattered bricks clutched in palms or glass bottles filled with accelerant and a dangling rag. In conversations with The Washington Post over the past several days, protesters from as near as South Minneapolis and as far as California have listed varied motivations for the unrest, from a desire to see additional officers charged in Floyd’s death, to general frustration with the police, to boredom during the coronavirus.

“They cancel the state fair, and this is what happens,” said one protester, who asked not to be named but said he was from Mankato, Minn.

Trump first pointed to antifa Saturday, tweeting, “It’s ANTIFA and the Radical Left. Don’t lay the blame on others!” Soon after, Barr appeared on TV in apparent support of the president, saying, “In many places, it appears the violence is planned, organized and driven by anarchic and left extremist groups, far- left extremist groups, using antifa-like tactics, many of whom travel from outside the state to promote the violence.”

Antifa, short for anti-fascist, is not a national group, but more of a far-left ideology spawned as a reaction to the far right, Bray said. In some places across the country, there are groups that call themselves “antifa” that “are very well organized and tightly knit,” he said. Some coordinate with one another.

The groups do not make their membership rolls public, so tracking their scope is difficult, but they generally have about five to 15 members in a given city, Bray said. That, he said, is why it is so difficult to believe they are primarily responsible for engineering the violence in so many places.

“If antifa on its own could orchestrate a national campaign of burning down police stations and burning down malls, they would have done it years ago,” Bray said. “They agree with these kinds of actions. But the number of people involved is so small.”

T.V. Reed, a Washington State University professor who studies protests and social movements, said conservative politicians have long “exaggerated the importance” of interlopers infiltrating protests, and they “are clearly doing it again.” But the matter, he said, can be complicated, as violent, right-wing extremists might see an opportunity to discredit the protests, and petty thieves seize the occasion to loot.

“There is simply no way at this stage to separate out all these competing elements,” Reed said. “But, bottom line, the heart of the protest is legitimately angry but nonviolent folks with a real set of grievances.”

A Justice Department spokeswoman said Barr’s allegation about far-left groups was based on “information given to us by state and local law enforcement.”

New York Police Department Deputy Commissioner of Intelligence and Counterterrorism John Miller said Sunday night that, before protests began, “organizers of certain anarchist groups set out to raise bail money and people who would be responsible to be raising bail money, they set out to recurit medics and medical teams with gear to deploy in anticipation of violent interactions with police,” according to NBC News. Miller added that they “developed a complex network of bicycle scouts to move ahead of demonstrators in different directions of where police were and where police were not for purposes of being able to direct groups from the larger group to places where they could commit acts of vandalism including the torching of police vehciles and molotov cocktails where they thought officers would not be.”

State and local officials in Minnesota, though, have given a different account.

Minnesota Gov. Tim Walz (D) suggested that white supremacists or drug cartels were perhaps responsible for the violence. The claim about white supremacists, state officials said, was based on a review of online postings, which showed far-right activist groups encouraging their followers to descend on the state. Federal law enforcement officials said they were not aware of any cartel involvement.

Minnesota Attorney General Keith Ellison told Fox News Sunday, “We have evidence that outsiders have been present and, in some cases, have played a very negative role.

“But I’ve been talking with protesters and trying to get a sense of who some of these folks are, and I’ve heard mixed things,” Ellison said. “Some of the negative stuff has come from people in Minnesota and some of it has come from people on the outside What I’d say is we’ve got enough to handle on our own and that what we really need to do is refocus on justice for Mr. Floyd.”

Jeremy Zoss, a spokesman for the Hennepin County, Minn., Sheriff’s Office, said in an email that 41 of the 52 people arrested on protest-related charges from 8 p.m. Saturday to 4 p.m. Sunday listed a Minnesota address. The others listed addresses in Wisconsin, Iowa, Oregon, Nebraska, North Dakota, Illinois and Australia.

Zoss said of that of the 73 people cited for curfew violations in the same period, 50 had Minnesota driver’s licenses. A dozen did not have a license and one license could not be matched to the person carrying it. The rest came from California, Colorado, Florida, Illinois, South Dakota and Texas, Zoss said.

Speaking in a call with reporters on Sunday, Army. Maj Gen. Jon Jensen, adjutant general of the Minnesota National Guard, said he had recommended to Walz that his troops be armed after the FBI alerted him to what he described as a “credible, lethal threat” against the Minnesota National Guard. It was not clear what the threat was.

Walz’s and Ellison’s offices did not respond to a request for additional information. The FBI declined to comment.

Although Trump vowed Sunday to designate antifa a terrorist organization, legal observers say it is impossible for him to do so with any domestic group. Barr’s statement Sunday did not say antifa would face such a label — which would give law enforcement greater ability to target its members and supporters for investigation and prosecution. He said the FBI’s 56 regional Joint Terrorism Task Forces would work with state and local authorities to “identify criminal organizers and instigators” in the demonstrations.

“The violence instigated and carried out by antifa and other similar groups in connection with the rioting is domestic terrorism and will be treated accordingly,” Barr said.

Some observers noted that Trump has not taken a similarly aggressive posture toward white supremacists. After the 2017 “Unite the Right” rally in Charlottesville, when an Ohio man who supported white supremacists plowed his car into a crowd of counterprotesters — killing a woman — Trump said there were “very fine people, on both sides.”

“The critics will say, ‘Why are you only doing this for antifa now? Why weren’t you designating these far-right groups — Atomwaffen and the Base — before?” said Javed Ali, a former senior White House counterterrorism official who left in 2018.

The Justice Department ultimately charged the driver of the car in Charlottesville with federal hate crimes. The department in 2018 also brought federal rioting charges against several members of the racist and anti-Semitic group known as the Rise Above Movement who traveled to the rally. Barr said Saturday he would take similar steps for those who cross state lines to riot.

The FBI has in recent months brought charges against several members of Atomwaffen and the Base. Observers fear that in Trump’s push against antifa, though, he is trying to criminalize a political ideology that is radically opposed to his own.

Last year, two Republican senators pushed a nonbinding resolution to label antifa as “domestic terrorists” in 2019. The resolution, co-sponsored by Sens. Ted Cruz (R-Tex.) and Bill Cassidy (R-La.), received pushback from civil liberties groups who expressed concerns over the mislabeling of all counter protesters.

“As this tweet demonstrates, terrorism is an inherently political label, easily abused and misused,” ACLU National Security Project Director Hina Shamsi said in response. “There is no legal authority for designating a domestic group. Any such designation would raise significant due process and First Amendment concerns.”

Bray, the historian and author, said that while it might not be possible for Trump to formally declare the ideology a terrorist organization, his wanting to do was troubling.

“If you were to hypothetically make that broad spectrum of radical left and anti-capitalist political activity terrorism, you would have an excuse to clamp down upon pretty much anything that is further to the left than the Democratic Party,” he said.

Klemko reported from Minneapolis. Missy Ryan, Shane Harris and Ellen Nakashima contributed to this report.