A police officer has shot dead a naked and unarmed black man in an Atlanta suburb in the US in the latest series of such incidents.

The officer was responding to an emergency call from an apartment complex after there were reports of suspicious activity of a man in the locality.

The victim was identified as 27-year-old Anthony Hill, who was shot twice by the officer, killing him on the spot. Local reports suggest the black man appeared to be mentally ill as he was behaving erratically when he was shot.

Dekalb County Chief of Police Cedric Alexander told reporters that the man ran towards the police officer despite repeated warnings forcing him to open fire.

Alexander added the white officer was also carrying a shotgun and pepper spray when the shooting took place.

"We have already, as many departments have begun to do, looked at how to expand our mental health training. It appears that we're seeing more and more of these cases across the country in which police are engaging with those who may be in distress," said Alexander.

He said the victim was "acting deranged, knocking on doors, and crawling around on the ground naked" when the police received the emergency call.

The Georgia Bureau of Investigation has initiated an investigation into the matter. The officer, a seven-year veteran in the police force, has not been identified and given administrative leave pending the probe.

The Atlanta shooting is the latest in a spate of similar incidents involving security forces, which are reeling under heavy criticism for using excessive force against unarmed people, especially blacks.