Updated at 7:27 p.m. ET

As overlapping crises convulse an anxious nation, President Trump on Sunday sought to cast blame for widespread protests gripping cities on "radical-left anarchists," while adding that the media "is doing everything within their power to foment hatred and anarchy."

The president has said that members of the loosely defined far-left group Antifa — short for "anti-fascists" — have led clashes with police and looting in cities across the U.S. since the killing of a black man in police custody in Minneapolis.

It's unclear if any group or groups are primarily responsible for escalating protests that began following George Floyd's death on May 25 as Minneapolis police officer Derek Chauvin held his knee on Floyd's neck.

Minnesota Gov. Tim Walz, a Democrat, has told the press that he'd heard unconfirmed reports that white supremacists were coming from elsewhere to stoke the violence.

In one tweet on Sunday, Trump said the U.S. "will be designating ANTIFA as a Terrorist Organization." It's something he has previously floated, and last year two Republican senators introduced a resolution that sought to designate the group as a domestic terrorist organization.

Following Trump's tweet, Attorney General William Barr said in a statement that "[f]ederal law enforcement actions will be directed at apprehending and charging the violent radical agitators who have hijacked peaceful protest."

Barr added: "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."

The clashes, spreading to dozens of cities across the U.S., follow a series of racist incidents and deaths of black people, including Floyd's on Monday.

Chauvin, now a former Minneapolis police officer, was seen on video kneeling on Floyd's neck while holding him in custody as Floyd pleaded that he couldn't breathe. Chauvin has been charged with third-degree murder and manslaughter. Three other officers present at the scene have been fired but not arrested or charged.

Protests and clashes that have since followed come at a time of unprecedented crisis for the country, with confirmed deaths from the coronavirus pandemic topping 100,000 and millions of people out of work as a result of broad business shutdowns. Minorities, including African Americans, have been disproportionately affected by COVID-19 deaths and pandemic-induced economic peril.

Trump addressed the demonstrations Saturday,striking a milder tone than he has on Twitter during prepared remarks following a space launch in Florida. He said Floyd's death "has filled Americans all over the country with horror, anger and grief." He added that he "understands the pain that people are feeling" and supports peaceful protest, but that "the memory of George Floyd is being dishonored by rioters, looters and anarchists."

"He should just sometimes stop talking"

Apart from Saturday's remarks, though, Trump has not often played a unifying role in recent days. His tweets about radical-left anarchists have also included criticism of Democratic leadership in Minnesota. In another tweet on Sunday, he blamed the mainstream media for fomenting "hatred and anarchy."

On Friday, Trump tweeted provocatively that "when the looting starts, the shooting starts," a phrase with a racist history that Trump said he was not aware of. Later on, he said his intent was not to make a threat but to register a statement of concern that armed violence can accompany looting.

Sen. Tim Scott, a South Carolina Republican, said on Fox News Sunday that the president's tweets about demonstrations turning violent are "not constructive."

Speaking on ABC's This Week, House Speaker Nancy Pelosi, D-Calif., said on Sunday morning that she's not paying attention to Trump's inflammatory tweets. Instead, she said he "should be a unifying force in our country. We have seen that with Democratic and Republican presidents all along. They have seen their responsibility to be the president of the United States, to unify our country and not to fuel the flame."

Also Sunday, Keisha Lance Bottoms — mayor of Atlanta, one city that has seen protests and clashes with police — told CBS' Face the Nation that Trump's tweets are "making it worse" and "he should just sometimes stop talking."

In his own statement on Saturday, former Vice President Joe Biden, the presumptive Democratic nominee for president, wrote that "Protesting [Floyd's killing] is right and necessary. It's an utterly American response. But burning down communities and needless destruction is not. Violence that endangers lives is not." He added that as president, he'd lead the conversation about turning the nation's "anguish to purpose."

Biden made an unannounced visit on Sunday to the site in Wilmington, Del., where protests had taken place the night before.

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