A group of around 100 demonstrators have gathered near the Bank of America Stadium in Charlotte to protest over the shooting death of a man by a police officer.

Video footage of a deadly encounter between Charlotte police and a black man shows his wife repeatedly telling officers he is not armed and pleading with them not to shoot her husband as they shout commands to drop a gun.

Protesters have massed on Charlotte's streets for a third night in the latest sign of mounting pressure for police to release video that could resolve wildly different accounts of the fatal shooting of a black man.

A protester is fighting for his life after being critically wounded at a dusk prayer vigil as authorities in North Carolina's largest city tried to quell public anger following the fatal shooting of a black man by a police officer.

Authorities in North Carolina are trying to quell public anger after a night of looting and arson added Charlotte to the list of US cities that have erupted in violence over the death of a black man at the hands of police.