Barrow County, Georgia - Police and ambulances rushed to a high school in Georgia on Wednesday after reports of an active shooter and possible injuries, with students evacuated from the scene and one suspect taken into custody.

The Georgia Bureau of Investigation (GBI) said it was responding to a "shooting" at Apalachee High School in the state's Barrow County.

"We have agents on site assisting local, state, and federal law enforcement w/ the investigation. One suspect in custody," the GBI said in a post on social media.

Earlier, US media reported school authorities had sent a message to parents saying they were enforcing a "hard lockdown after reports of gunfire."

"Law enforcement is here. Please do not attempt to come to the school at this time while officers work to secure the area," it added.

CNN, citing the local sheriff's office, reported that there had been casualties without providing further details.

At least one air ambulance took a patient from the scene, according to footage from the scene.

The school is located in the town of Winder, about 45 miles northeast of Atlanta, the state capital.

Georgia Governor Brian Kemp said on X that state agencies were responding to the incident.

The White House said President Joe Biden had been briefed on the shooting.

Local television footage showed ambulances driving across a school field and scores of vehicles parked around the school. A crowd of people was visible on the football field.

Per CNN, a law enforcement source has revealed that at least two people were killed in Wednesday's shooting.

Atlanta's Grady Health System has received one gunshot wound victim, who was airlifted to the hospital.

At least four are now reported to have died in the shooting, with about 30 more said to have been injured, according to CNN.

The suspect is believed to be around the age of a high school student, but it is not currently known whether they attended Apalachee High.

US Attorney General Merrick Garland described a school shooting Wednesday in the state of Georgia as a "terrible tragedy" after local media reported four people were killed in the attack.

"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.

President Joe Biden said he was mourning the four deaths, saying Americans can no longer "accept this as normal."

"What should have been a joyous back-to-school season in Winder, Georgia, has now turned into another horrific reminder of how gun violence continues to tear our communities apart," the president said.

"We cannot continue to accept this as normal," he added.

Law enforcement has identified the suspect shooter as 14-year-old Apalachee High student Colt Gray, per CNN.

Gray, who "immediately surrendered" to police when confronted, will be charged with murder over the shooting and will be tried as an adult.

Georgia Bureau of Investigation Director Chris Hosey also confirmed that the four victims who were killed were two students and two teachers.