A police officer in the US has been fired after he was filmed repeatedly punching a black man during a traffic stop.

The deputy who has not been named has been sacked for "excessive use of force" on Roderick Walker, Clayton County Sheriff's Office in Georgia said.

A criminal investigation is under way.

Mr Walker was arrested on Friday after officers pulled over the vehicle he was travelling in for an alleged broken rear light.

The 26-year-old was with his girlfriend, their five-month-old child and his stepson at the time, his lawyer Shean Williams said.

Why would you demand ID of the passenger when its a broken tail light? The driver is right there. Did they even give the driver a citation for this supposed issue?
It doesn't add up#RoderickWalker#ThisIsAmerica

— The Black Mamba (@msonemic) September 13, 2020

The officers asked for Mr Walker's identification and demanded he get out of the vehicle when he questioned why they needed it since he was not driving, the lawyer added.

The subsequent arrest, which was filmed by a bystander and shared widely on social media, shows two officers on top of Mr Walker, one of whom repeatedly punches him.

Mr Walker's girlfriend screams and tells the officers that her partner said he cannot breathe.

A child in the vehicle is heard yelling: "Daddy."

As Mr Walker is handcuffed, the officer who punched him tells the bystander that the suspect bit him.

Mr Williams said his client denies biting the deputy and Mr Walker lost consciousness at least twice during the beating.

A photo of Mr Walker taken later in jail shows him with a badly bruised eye.

No one should be treated this way. #RoderickWalker is a son, brother, father and native of Atlanta. Release him from the Jail.

We’re protesting tomorrow at the Clayton County Jail Tomorrow at 2 pm. ✊🏾✊🏾✊🏾#NoJusticeNoPeace pic.twitter.com/NpXvtlWs9i

— Jared Sawyer Jr. (@JaredSawyerJr) September 13, 2020

Mr Williams said: "My reaction to the video is that it just shows unfortunately another incident where an African American male's civil rights have been violated by people and officers and law enforcement who have the duty first to protect and serve."

Mr Walker was arrested on suspicion of obstructing officers and battery.

His lawyer demanded his release on bond and said he has asked the Georgia Bureau of Investigation to review the case.

Mr Williams also accused investigators of improperly talking to his client without an attorney at the jail.

pic.twitter.com/QXLrjYIxSO #RoderickWalker is Asked for his ID When is Lyft Driver is pulled Over by Police. Mr Walker questions the Request Since he Wasn’t Driving. This is The Officer’s Response.
Please Call 678-479-5300 To Demand that’s These Animals be Named Fired Charged.

— koree ,model,superstar,activist (@superstarboss1) September 13, 2020

The sheriff's office said a court denied bond for Mr Walker because of outstanding warrants, which included one for cruelty to children and another for possession of a firearm by a convicted felon.

Mr Walker had received medical attention and was being monitored by a doctor at the jail hospital, the sheriff's office added.

The incident comes after months of protests over police violence and racial injustice in America following the killing of George Floyd while in police custody in Minneapolis in May.

There were further violent demonstrations after Jacob Blake was left paralysed when he was shot seven times by police in Wisconsin last month.