Footage of a traffic stop that has seen five ex-Memphis police officers charged with murder shows them kicking and punching a motorist for several minutes as he cries out for his mother.
Officers are seen beating Tyre Nichols, 29, in the videos from the 7 January arrest, with no signs of him resisting.
US President Joe Biden said he was “deeply pained” by the “horrific” clip.
Lawyers for Mr Nichols’ family likened the assault to the 1991 police beating of Los Angeles motorist Rodney King.
Peaceful protests took place in Memphis on Friday night after the video was released, with some demonstrators blocking a major highway in the city, while small-scale demonstrations were held elsewhere in the country.
Many protesters held banners demanding justice for Mr Nichols and an end to “police terror”.
Mr Nichols was black, as are all five officers charged in the case.
Memphis Police Department released four graphic videos of the traffic stop and its violent aftermath on Friday, totalling more than an hour of footage.