Former Minneapolis police Officer Derek Chauvin has pleaded guilty to a federal charge of violating George Floyd’s civil rights, averting a trial but likely extending the time he is already spending behind bars on a state conviction.

Chauvin, who is white, was convicted of state murder and manslaughter charges for pinning his knee against Mr Floyd’s neck during a May 25, 2020, arrest as the black man said he couldn’t breathe.

Chauvin was sentenced to 22 and a half years in that case.

The federal charge alleged that Chauvin deprived Mr Floyd of his rights by kneeling on his neck as he was handcuffed and not resisting.

Chauvin appeared in person on Wednesday for the change of plea hearing in an orange short-sleeve prison shirt and was led into and out of the court in handcuffs.

He said “Guilty, your honour” to confirm his pleas in Mr Floyd’s death and an unrelated 2017 case, and acknowledged that he was guilty of the acts alleged.

With parole and presuming good behaviour, Chauvin is expected to actually serve about 15 years of his state sentence behind bars.

Any federal sentence would run at the same time as the state sentence and defendants serve about 85 per cent of federal sentences presuming good behaviour.

That means if the judge gives Chauvin the maximum 25 years requested, he would likely serve about six years and three months beyond his state sentence.

Judge Paul Magnuson did not set a date for sentencing.

Three other former officers – Thomas Lane, J. Kueng and Tou Thao – were indicted on federal charges alongside Chauvin earlier this year.

They are still on course for trial early next year on those charges, with a state trial still to come.

Mr Floyd’s arrest and death, which a bystander captured on mobile phone video, sparked mass protests across the US calling for an end to racial inequality and police mistreatment of black people.

As part of the plea deal, Chauvin also pleaded guilty to violating the rights of a then-14-year-old boy during a 2017 arrest in which he held the boy by the throat, hit him in the head with a flashlight and held his knee on the boy’s neck and upper back while he was prone, handcuffed and not resisting.

Video showed George Floyd’s under the knee of a Derek Chauvin. Photo: Danella Frazer

Several members of Mr Floyd’s family were present, as was the then-teenager involved in the 2017 arrest, according to a pool reporter.

As they left the courtroom, Mr Floyd’s brother Philonise said to Chauvin’s 2017 victim: “It’s a good day for justice.”

Nine people appeared to support Chauvin, including family members.

He waved and smiled at them as he entered and left the courtroom, according to the pool report.

Mr Floyd’s nephew, Brandon Williams, afterward called Chauvin a “monster” who should have been arrested in the 2017 incident.

“Had he been held accountable for what he did in 2017 to that minor, George Floyd will still be here,” Mr Williams said.

“Today he had a chance to blow kisses and give air hugs to his family. We can’t do that.”

-AAP