The city of Memphis released graphic video footage on Friday of the violent encounter between Tyre Nichols, a 29-year-old Black man, and the five police officers charged with murder in his beating death after a traffic stop earlier this month.

One video clip shows officers dragging Nichols from the driver's seat of his car as he yells, "Damn, I didn't do anything ... I am just trying to go home," and force him to the ground as they order him to lay on his stomach, then squirt him in the face with pepper spray.

Nichols breaks free, scrambles to his feet and sprints off down a road with officers in pursuit, firing stun guns at him.

A separate video shows a subsequent struggle after officers catch up with Nichols again, and are beating him. Two officers are seen holding him down as a third one kicks him and a fourth delivers blows with what appears to be a rod before another punches Nichols.

The four segments of highly anticipated footage from police body-worn and dashboard cameras were posted online Friday evening a day after the officers were charged with second-degree murder, assault, kidnapping, official misconduct and oppression.

The officers, all Black, had already been dismissed from the police department last Saturday following their January 7 confrontation with Nichols after pulling him over.

He succumbed to his injuries and died three days later while hospitalised.

Memphis police chief Cerelyn Davis and lawyers for Nichols' family who watched the video with his relatives before it was released, warned in advance that the images were brutal and likely to cause outrage, while appealing to the public for calm.

"You are going to see acts that defy humanity," Davis told CNN in describing the footage.

Civil rights attorney Ben Crump, representing Nichols' family, said the last words on the video were Nichols crying out for his mother.

"No mother should go through what I am going through right now, no mother, to lose their child to the violent way that I lost my child," Tyre Nichols' mother, RowVaughn Wells, said on Friday.

The footage was likely to transform Nichols, the father of a 4-year-old described as an affable, accomplished skateboarder who recently enrolled in a photography class, into the next face of the US racial justice movement.

Raised in Sacramento, California, Nichols moved before the coronavirus pandemic to the Memphis area, where he lived with his mother and stepfather and worked at FedEx, taking a break each day to come home for a meal prepared by his mother.

Nichols' family and President Joe Biden have appealed for protests to stay peaceful in Memphis, a city of 628,000 where nearly 65 percent of residents are Black. Schools were scheduled to close early and Saturday morning events were cancelled.

Biden spoke with RowVaughn Wells and Rodney Wells, Nichols’ stepfather, on Friday afternoon to express his condolences, the White House said, adding that it was coordinating with relevant government agencies in case protests turn violent.

Nichols' death marked the latest high-profile instance of police officers accused of using excessive force in the deaths of Black people and other minorities in recent years. These have been publicly condemned as systemic racism in the US criminal justice system.

Protests under the banner of the "Black Lives Matter" movement against racial injustice erupted globally following the May 2020 murder of George Floyd, a Black man who died after a white Minneapolis police officer knelt on his neck for more than nine minutes.

Antonio Romanucci, another lawyer for Nichols' family, told National Public Radio in an interview on Friday that Nichols was a strong supporter of the Black Lives Matter movement and "basically died for his own cause."

US Attorney General Merrick Garland on Friday announced a federal civil rights investigation into Nichols' death, while law enforcement agencies in some major cities, including New York, Atlanta and Washington, said they were preparing for possible protests following the video's release.

The White House said it held a conference call with mayors from several cities to brief them on federal preparations for the anticipated release of the footage and asked the mayor to remain in regular contact in the coming days.

Police have described the circumstances of Nichols' arrest in vague terms. Even Shelby County District Attorney Steve Mulroy, who sought the officers' indictment, was circumspect when announcing the charges.

After Nichols was pulled over for reckless driving, "an altercation" ensued in which officers doused him with pepper spray, and Nichols tried to flee on foot, Mulroy said. "There was another altercation at a nearby location at which the serious injuries were experienced by Mr. Nichols."

Davis said her department has not yet been able determine whether there was probable cause for the officers to pull Nichols over for reckless driving, a traffic stop which set in motion the violent events that followed.

Crump said the speed at which the criminal charges were brought against the officers - fewer than three weeks after Nichols' death - should be a standard for police-involved killings.

In some other high-profile cases, such as the police killing of Laquan McDonald in Chicago in 2014, more than a year elapsed before the release of police video and the filing of charges.

"We want to proclaim that this is the blueprint going forward for any time any officers, whether they be Black or white, will be held accountable," Crump said. "No longer can you tell us we got to wait six months to a year.”

Lawyers for the family also called on the police department to disband the special SCORPION unit focused on violent street crime to which at least some of the officers were assigned. Davis has said the department will review SCORPION and other specialised units.

Crump compared the encounter to the 1991 videotaped beating of Black motorist Rodney King by four police officers whose subsequent acquittal of criminal charges sparked days of riots in Los Angeles.

All five officers - Tadarrius Bean, Demetrius Haley, Emmitt Martin III, Desmond Mills Jr., and Justin Smith - were fired from the police force on January 21 after an internal investigation found they breached multiple department policies, including use of excessive force.

Four of the officers have posted bail and have been released from jail, a CBS affiliate reported on Friday. A lawyer for Mills, Blake Ballin, said it might be another two weeks before the defendants make their initial court appearances. (Reuters)