Attorney General William P. Barr on Friday directed the formation of a task force that will be dedicated to countering “anti-government extremists,” escalating federal law enforcement’s response to the violence that has sometimes marked nationwide protests against police brutality and racism, according to a memo obtained by The Washington Post.

In the memo, Barr wrote that amid peaceful demonstrations, anti-government extremists had “engaged in indefensible acts of violence designed to undermine public order.”

“Among other lawless conduct, these extremists have violently attacked police officers and other government officials, destroyed public and private property, and threatened innocent people,” Barr wrote in a directive to all the Justice Department’s law enforcement components and U.S. attorneys. “Although these extremists profess a variety of ideologies, they are united in their opposition to the core constitutional values of a democratic society governed by law. . . . Some pretend to profess a message of freedom and progress, but they are in fact forces of anarchy, destruction, and coercion.”

Barr’s memo said that, in the past month, the Justice Department had disrupted extremists “of all persuasions,” and he singled out two: “those who support the ‘Boogaloo,’ ” a radical right-wing group whose adherents openly anticipate civil war, and “those who self identify as Antifa,” a far-left-leaning ideology that encompasses communists, socialists and anarchists.

“Some of these violent extremists, moreover, may be fortified by foreign entities seeking to sow chaos and disorder in our country,” Barr wrote, though he offered no specifics.

Barr has previously warned of a “witch’s brew” of extremist groups taking advantage of the protests to incite mayhem, and he has singled out in particular antifa, which President Trump also has sought to blame for violence at demonstrations. That has drawn some criticism, because of more than 120 people the department has charged federally with protest related crimes, none has been alleged to have ties to an organized antifa group, according to public summaries of the cases.

The vast majority of those charged seem to be individual actors intent on sowing chaos. And they represent a minuscule fraction of the thousands who have peacefully protested police violence and racism throughout the country.

According to Barr’s memo, the task force will be led by Craig Carpenito, the U.S. attorney for New Jersey, and Erin Nealy Cox, the U.S. attorney for the Northern District of Texas, and it will include representatives from the FBI and federal prosecutor shops across the country. Barr wrote that it would develop information about “extremist individuals, networks, and movements” and share that data with local law enforcement. The group will also provide training and resources to local authorities to help prosecute anti-government extremists, Barr wrote.

“The ultimate goal of the task force will be not only to enable prosecutions of extremists who engage in violence, but to understand these groups well enough that we can stop such violence before it occurs and ultimately eliminate it as a threat to public safety and the rule of law,” Barr wrote.

Adhering to a radical ideology, right or left, is not a crime, and the task force might face legal limitations in what it can investigate.

In an interview with NPR on Thursday, Barr said the Justice Department has “approximately 300 investigations” nationwide, some involving people who identify as “antifa.” Asked why the department had not made any such public allegations in court, Barr said that in early proceedings, the department doesn’t charge people with being members of antifa, but rather, for crimes such as throwing a molotov cocktail or possessing a gun.

“But we are building. We are obtaining information and intelligence about the operations of these people,” he said.

The Anti-Defamation League has tracked dozens of instances of what it calls a “small but vocal array” of right-wing extremists appearing at protests. In New Mexico earlier this month, an armed militia group showed up at a demonstration to tear down a monument to Spanish conquistador Juan de Oñate, a 16th-century despot who massacred indigenous people. After the group clashed with those wanting the statue to come down, a man was shot — though members of the group have said they did not know the shooter or the victim.

Trump has recently taken aim at those seeking to topple monuments, particularly after demonstrators tried to bring down a bronze statue of President Andrew Jackson in a park next to the White House on Monday. The attempt was thwarted by police, but the next morning, Trump vowed severe punishment for those seeking to vandalize monuments, tweeting that he had “authorized the Federal Government to arrest anyone who vandalizes or destroys any monument, statue or other such Federal property in the U.S. with up to 10 years in prison, per the Veteran’s Memorial Preservation Act, or such other laws that may be pertinent.....”

In the days that followed, the Army activated about 400 unarmed members of the Washington, D.C., National Guard to “prevent any defacing or destruction” of monuments, and U.S. marshals were told — apparently at Barr’s request — they should prepare to help protect monuments across the country. The FBI on Friday put out a wanted poster seeking information on people it suspects were involved in Monday’s incident.

The Justice Department has brought charges against several people who consider themselves members of the Boogaloo movement. Most notably, federal prosecutors in California charged Air Force Staff Sgt. Steven Carrillo, who they say is an adherent of the Boogaloo ideology, with shooting and killing a Federal Protective Service officer outside a federal courthouse in Oakland.

Officials said at a news conference that Carrillo, who is also charged in the murder of a Santa Cruz County Sheriff’s sergeant, thought it would be easier to target law enforcement and get away during demonstrations over police violence.