May 29 (UPI) — A former Minneapolis police officer seen kneeling on the neck of George Floyd before he died during an arrest this week has been charged with murder, Minnesota prosecutors said Friday.

Hennepin County Attorney Mike Freeman announced that Derek Chauvin had been charged with third-degree murder in connection with Floyd’s Monday death.

Floyd was pronounced dead after his arrest on suspicion of using a counterfeit bill at a grocery store. Video of the African-American man gasping for breath as the white police officer kneeled on the back of his neck for several minutes quickly circulated online, igniting a four-day wave of protests and rioting in the Twin Cities and elsewhere in the country.

Chauvin was taken into custody earlier Friday by the state Bureau of Criminal Apprehension.

Freeman said prosecutors were still reviewing the evidence and indicated there could be further charges brought against Chauvin.

He and three other officers involved in Floyd’s death were fired from the Minneapolis Police Department shortly after the video was released. Freeman said investigations of the others were ongoing.

“We felt it appropriate to focus on the most dangerous perpetrator,” he said, adding that his office has never before brought murder charges within only a four-day time span.

Among the evidence against Chauvin, he said, was the citizen’s video, the officers’ body cameras, witness statements, a preliminary medical examiner’s report and expert testimony.

Minneapolis Council Member Andrea Jenkins told MSNBC that Floyd and Chauvin worked together as security guards at the same Minneapolis restaurant for 17 years.

“Officer Chauvin, he knew George for a very long time,” Jenkins said.

The charges came hours before Minnesota Gov. Tim Walz signed an executive order instituting an 8 p.m. curfew in Minneapolis and St. Paul as the cities geared up for a fourth night of protests.

“it’s time to rebuild our community and that starts with safety in our streets,” Walz said.

“Thousands of Minnesotans have expressed their grief and frustration in a peaceful manner. But the unlawful and dangerous actions of others, under the cover of darkness, has caused irreversible pain and damage to our community. This behavior has compromised the safety of bystanders, businesses, lawful demonstrators and first responders. Now, we come together to restore the peace.”

Roseville, Minn., Mayor Dan Roe also imposed an 8 p.m. curfew and issued an emergency declaration,

Protests broke out for a fourth evening Friday across the country, with demonstrations turning violent in some instances.

California Highway Patrol spokeswoman Alicia Moreno told CNN that protesters threw projectiles at officers and vandalized vehicles in San Jose. Demonstrators also clashed with police in Brooklyn near the Barclays Center.

Demonstrators have also gathered outside the White House, which was placed on lockdown.

In Atlanta, protesters erected a Black Lives Matter flag on the CNN sign, which was also spray painted. Some demonstrators also burned an American flag and broke glass at the CNN Center.

Protests were also reported in Houston, Dallas, Louisville, Ky., and Wisconsin.

In Minneapolis, where Floyd was killed, protesters changed “I can’t breathe” — among Floyd’s last words — and took a knee for 9 minutes, the amount of time the criminal complaint says Chauvin kneeled on Floyd’s neck.

Late Thursday, demonstrators set fire to a police precinct building in the neighborhood where Floyd died. The building had been evacuated by order of Mayor Jacob Frey, who said he was unwilling to endanger lives to protect the building.

“I understand the importance of a precinct,” he said. “[But] the symbolism of a building cannot outweigh the importance of life, of our officers, or the public. We could not risk serious injury to anyone and we will continue to patrol the third precinct entirely.”

At 4:30 a.m. Friday, protesters and looters still were out on the streets in the neighborhood as several nearby commercial buildings burned unchecked.

Firefighters arrived shortly afterward, accompanied by state police in riot gear, who began to arrest people in the area, including a CNN reporter and crew members.

CNN correspondent Omar Jimenez and three crew members were taken into custody live on the air. The news organization immediately criticized the arrests and called for their release.

Minnesota Gov. Tim Walz said later in the morning he “took full responsibility” for incident while issuing a “very public apology” to CNN.

“There is no reason something like this should happen,” he said.

The unrest also spread to neighboring St. Paul, where protesters looted a Target store and set fire to several businesses along a busy commercial corridor.

Earlier in the night, National Guard troops were deployed in the two cities at Walz’s order.

The governor said he issued the order at the request of local leaders who called on the state government for National Guard resources after “extensive damage to private property” occurred during the protests.

At a press conference early Friday, Frey responded to President Donald Trump, who tweeted about the Minnesota protests. In the post, he called Frey “a very weak radical left mayor” and said, “when the looting starts, the shooting starts.”

Twitter flagged Trump’s tweet as violating its rules and “glorifying violence.”

“Weakness is refusing to take responsibility for your own actions,” Frey told reporters.

“Weakness is pointing your finger at somebody else, during a time of crisis. Donald Trump knows nothing about the strength of Minneapolis. We are strong as hell. Is this a difficult time period? Yes. But you better be damn sure that we’re going to get through this.”

Racially charged unrest over Floyd’s death and similar police brutality cases spread across the United States late Thursday. Protests occurred from coast to coast.

In Louisville, Ky., seven people were shot during a protest over the shooting death of local resident Breonna Taylor during a March police raid.

Louisville Mayor Greg Fischer said in an early morning video message the shootings came from within the crowd. Five of those wounded were not seriously hurt, while two were sent into surgery and one was in critical condition.

“No officers fired their weapons,” he said, thanking them for directing aid to the injured demonstrators “despite the risk to themselves.”

The shots were fired around 11:30 p.m. as protesters gathered near the Louis D. Brandeis Hall of Justice. They were attempting to overturn a police prison transport vehicle before in the moments before the gunfire, video showed.

In New York City, more than 70 people were arrested Thursday night as protesters broke COVID-19 lockdown rules to protest Floyd’s death.

Five were charged with felonies for assaulting police officers — three of whom were injured in the melee — NYPD Chief of Department Terence Monahan said, adding police will be ready for more protests Friday and over the weekend.

“There will be a very large police presence there,” he said. “We expect that these will be peaceful, that people will express their outrage on the incident that happened in Minnesota, and rightly so.

“But we’ll be out there to make sure we keep the peace. And if there are any agitators within the group, if we need to make that arrest, we’ll single that individual out, we’ll take him and allow the other peaceful protesters to go on.”

In Columbus, Ohio, protests over Floyd’s death turned violent when some demonstrators began to throw objects at police. Officers responded by firing tear gas.

Protesters later broke windows at the Ohio Statehouse and entered the building. Police tactical squads quickly responded.

Widespread vandalism and property damage was reported in the city.

As the weekend approached with the likelihood of more protests, the Mall of America in suburban Minneapolis announced it has delayed a planned partial reopening.

“Out of an abundance of caution, given the significant unrest in the community, Mall of America has decided to postpone its planned June 1 reopening of retail stores,” Mall officials said in a website post, adding that curbside pick-up had also been suspended.

“Our top priority is the safety of our tenants, their employees, and our team members; and restricting access to the building will allow us to do that,” they told NBC News. “By delaying our reopening date, it will give mall retailers additional time to prepare.”