Four people were killed and nine wounded in a school shooting in the US state of Georgia on Wednesday, the state bureau of investigation said.

"Four dead. An additional nine taken to various hospitals with injuries. Suspect in custody and alive. Reports that the suspect has been 'neutralized' are inaccurate," the bureau said in a social media post – cited by Agence France-Presse (AFP).

The US Attorney General Merrick Garland described the shooting a "terrible tragedy.”

"I'm devastated for the families who have been affected by this terrible tragedy," the top US Justice Department official told reporters, minutes after Barrow County Sheriff Jud Smith said there were "multiple injuries" and a suspect was in custody.