The US police officer accused of George Floyd's murder told him to stop talking as he repeatedly gasped under the man's knee, according to court documents.

The unarmed black man cried out for his late mother and children as he said the Minneapolis policeman would kill him, transcripts from body-cam footage show.

They were disclosed in court by lawyers for one of the four officers involved.

The documents offer the clearest picture yet of Mr Floyd's last moments. His death in May sparked global uproar.

It led to a wave of anti-racism protests led by the Black Lives Matter movement, and stirred debate and reflection in the US over the country's history of slavery and segregation.

All four officers involved in taking Mr Floyd into custody were fired and arrested. Derek Chauvin, who knelt on his neck, faces several charges including second-degree murder, while the other three - Thomas Lane, J Alexander Kueng and Tou Thao - are charged with aiding and abetting murder.

The transcripts were made public on Thursday as Mr Lane's lawyers asked for the case against him to be dismissed.

Warning: Some readers may find the content below distressing.

What do the transcripts show?

Until now, eyewitness footage shared on social media revealed most of what was known about Mr Floyd's arrest and his final moments.

The new transcripts give a more detailed account, shedding light on significant parts of the encounter, from the time Mr Lane and Mr Kueng arrived at the scene, to the point where Mr Floyd was given CPR in an ambulance.

Transcripts of footage recorded by body cameras fitted to Mr Lane and Mr Kueng show Mr Floyd said more than 20 times he could not breathe as he was restrained by the officers in a Minneapolis street.

They confronted him outside a convenience store where he was suspected of having used a forged $20 note to buy cigarettes.

At one point, a handcuffed Mr Floyd, while pinned down on the road next to the police car, gasps that he cannot breathe, adding: "You're going to kill me, man."

Mr Chauvin, who is shown in bystander footage appearing to kneel on Mr Floyd's neck for nearly eight minutes, replies: "Then stop talking, stop yelling.

"It takes heck of a lot of oxygen to talk."

The transcripts show Mr Floyd appears co-operative at the beginning of the arrest, repeatedly apologising to the officers after they approach his parked car.

Mr Lane asks Mr Floyd to show his hands at least 10 times before ordering him to get out of the vehicle.

In response to one of the demands to see his hands, Mr Floyd says: "Man, I got, I got shot the same way, Mr Officer, before." It is not clear what he is referring to.

At one point Mr Lane says: "Why's he getting all squirrelly and not showing us his hands and just being all weird like that?"

The officers then handcuff Mr Floyd and try to put him into the back of their police car. As they do, Mr Floyd becomes agitated, repeatedly pleading that he is claustrophobic.

Mr Lane asks if he is "on something". Mr Floyd replies: "I'm scared, man."

According to another document, Mr Lane told investigators that once in the car, Mr Floyd began "thrashing back and forth"

Officers then pulled him out of the car and to the ground. Pinned on the floor, according to the transcript, Mr Floyd cries out a dozen times: "Mama."

He says: "Can't believe this, man. Mom, love you. Love you.

"Tell my kids I love them. I'm dead."

At one point, when Mr Floyd continues to plead he can't breathe, Mr Lane asks Mr Chauvin: "Should we roll him on his side?"

The officer responds: "No, he's staying put where we got him."

Mr Chauvin's lawyers have not commented on the documents since they were made public.