Chauvin pleaded guilty to the federal civil rights charges in December in the U.S. District Court in St. Paul, Minnesota, a decision that averted a second trial but almost certainly extended his time behind bars.

Chauvin, who is white, admitted he violated Floyd's right not to face "unreasonable seizure" by kneeling on the handcuffed Black man's neck for more than 9 minutes in a murder captured on cellphone video that horrified people around the world.

A state court has already sentenced Chauvin to 22-1/2 years in prison for intentional second-degree murder, third-degree murder and second-degree manslaughter. People sentenced to prison for felonies in Minnesota are usually released on parole after serving two-thirds of their sentence.

Chauvin's guilty plea to the federal charges came as part of an agreement with prosecutors that said he would face between 20 and 25 years in federal prison.

In that agreement he admitted for the first time that he was to blame for Floyd's death.

Floyd could be seen in videos pleading for his life before falling still on the road beneath Chauvin's knee. A medical examiner ruled the police restraint stopped Floyd from being able to breathe.

Federal prosecutors have asked Judge Paul Magnuson to sentence Chauvin to 25 years, a sentence that would run concurrently with the state one.

Floyd's murder sparked one of the biggest protest movements seen in the United States, with daily marches to decry racism and brutality in U.S. policing. Chauvin was helping three colleagues to arrest Floyd in May 2020 on suspicion Floyd had used a fake $20 bill when buying cigarettes.

The three other former police officers who worked to arrest Floyd -- Tou Thao, J. Alexander Keung and Thomas Lane -- were found guilty in the same federal court in February of violating Floyd's rights. They are yet to receive a sentencing date.

(Reporting by Jonathan Allen in New York; Additional reporting by Dan Whitcomb in Los Angeles; Editing by Bradley Perrett)