WINDER, Ga. (AP) — At least four are dead and four people are injured after a school shooting at a Georgia high school, which was put on lockdown Wednesday and students gathered in its football stadium, local law enforcement said.

One suspect was in custody, the Barrow County Sheriff’s Office said in a statement. CNN reports that the suspect is believed to be a 14-year-old boy, but it is unsure whether or not he attended the school. 

All schools in the district were placed in lockdown, and police were sent out of an abundance of caution to all district high schools, but there are no reports of secondary incidents or scenes, sources told CNN. The high school also received an earlier phone threat warning of shootings at five schools and that Apalachee was to be the first, multiple law enforcement officials told CNN. It is not known who placed the call.

According to CNN, Grady Health System in Atlanta received one gunshot victim from the shooting at Apalachee High School. Some of the critically injured were removed by helicopter, and additional helicopters are on standby. An adult with a gunshot wound to the stomach and a minor with unspecified injuries are being treated at an Athens hospital, CNN also reports.

Shortly before 10:30 a.m., “officers from multiple law enforcement agencies and Fire/EMS personnel were dispatched to the high school in reference to a reported active shooting,” the sheriff’s office statement said.

Helicopter video from WSB-TV showed dozens of law enforcement and emergency vehicles surrounding Apalachee High School in Barrow County, about 50 miles northeast of Atlanta.

“I have directed all available state resources to respond to the incident at Apalachee High School and urge all Georgians to join my family in praying for the safety of those in our classrooms, both in Barrow County and across the state,” Georgia Gov. Brian Kemp said in a statement.

“We will continue to work with local, state, and federal partners as we gather information and further respond to this situation,” Kemp added.

In a statement, the FBI’s Atlanta office said: “FBI Atlanta is aware of the current situation at Apalachee High School in Barrow County. Our agents are on scene coordinating with and supporting local law enforcement.”

Calls and messages to the Barrow County Sheriff’s Office and the school were not immediately returned.

Apalachee High School has about 1,900 students, according to records from Georgia education officials. It became Barrow County’s second-largest public high school when it opened in 2000, according to the Barrow County School System. It’s named after the Apalachee River on the southern edge of Barrow County.

The shooting had reverberations in Atlanta, where patrols of schools in that city were beefed up, authorities said. More patrols of Atlanta schools would be done “for the rest of the day out of an abundance of caution,” Atlanta Mayor Andre Dickens said.

President Joe Biden and Vice President Kamala Harris have also been briefed on the situation's status. The “administration will continue coordinating with federal, state, and local officials as we receive more information,” the White House told CNN.

"Students across the country are learning how to duck and cover instead of how to read and write. We cannot continue to accept this as normal," Biden said in a statement.