The U.S. city of Memphis on Friday released graphic video footage showing the fatal police assault of a 29-year-old Black man, as cities braced for a night of protests against police brutality.

The newly-released footage from police body cameras shows a group of officers detaining Tyre Nichols, attempting to take him down with the use of a Taser, then giving chase as he evades them.

Subsequent segments — the footage runs about an hour in total, and is audio-only in parts — show Nichols crying out for his mother, and moaning as officers repeatedly kick and punch him.

In one extremely graphic video, officers are seen aiming several kicks at Nichols' face. After pulling him up, they deliver five punches to his face. When he falls to the ground they aim two more kicks at his face.

U.S. President Joe Biden declared himself "outraged and deeply pained" Friday by the newly released footage. 

"The footage that was released this evening will leave people justifiably outraged," Biden said in a statement, urging protesters to remain peaceful. "Those who seek justice should not resort to violence or destruction," Biden said.

Five former Memphis police officers were charged on Thursday with murder in the death of Tyre Nichols, who died on January 10, three days after a traffic stop, prosecutors said.

'Ending police terror'

In downtown Memphis, around 50 protesters gathered at the central Martyrs Park to mark the video's release, later blocking a main road as they marched and chanted "No Justice, No Peace" and "Say His Name: Tyre Nichols."

Around 100 people gathered in New York's Times Square, chanting similar slogans and holding banners reading "End police terror."

Memphis Police Chief Cerelyn Davis compared the video to footage of the 1991 Rodney King beating. The 1992 acquittal of officers who beat King sparked days of riots in Los Angeles that left more than 60 people dead and wrought $1 billion in damage.

The young man's death also drew immediate comparisons with the May 2020 killing of George Floyd, another Black man whose suffocation by a white police officer in Minneapolis was likewise caught on video.

Several cases of police officers using excessive force on Black people in the United States over the years have not only revived scrutiny of race relations and a culture of police brutality in the United States but have also been condemned by the public and led to calls for changes in policies. 

UC Berkeley's Glaser told AFP that there was a cultural shift underway that recognized the prevalence of police violence against Black men.

But, he said, headline-grabbing incidents like the death of Tyre Nichols were just "those above the waterline" that we become aware of because of the video and because of the level of violence involved.

"This is the thing that indicates how bad the biases are and how out-of-kilter the policing mindset is."

(With input from agencies)