Police in Atlanta, Georgia have named the gunman who shot dead four people in a quiet residential suburb yesterday.

33-year-old Cedric G Prather took his own life after shooting six people in Douglasville, about 30km west of Atlanta.

The local sheriff's office says two other children remain in a critical condition in hospital tonight.

Police had earlier said said a man shot several people, including his ex-wife and a number children, on a quiet suburban street outside Atlanta, neighbours and US police say.

Douglas County Sheriff's Lt Glenn Daniel said the shooter then turned the gun on himself.

Officers were called to the housing development, west of Atlanta, shortly after 3pm local time.

The shooter appeared to have targeted his ex-wife and her household, including several children who tried to flee, Lt Daniel said.

The victims were shot inside and outside the house, police say.

Neighbours called police and treated the severely injured victims as best they could before rescuers arrived.

They described hearing "police car after police car" and several police helicopters.

"It's very devastating, nothing ever really happens here," one resident said.

Investigators are still trying to establish the shooter's motive and piece together what happened.

"I've been in law enforcement out here 20 years and this is the worst I've ever seen," Lt Daniel said.

Teresa Carter (59) told Associated Press news agency that she heard gunfire from inside the house.

"I heard shots, and I heard the girl scream. And then I heard four more shots" she said.