The 14-year-old gunman, who injured three people at a South Carolina elementary school before being arrested, carried out the attack after killing his father.
A South Carolina teenager shot and killed his father then drove to an elementary school where he opened fire with a handgun, wounding two children and a teacher before being tackled by a firefighter who held him for police, authorities said on Wednesday.
The suspect, whose name has not been released, was accused by police of shooting dead his 47-year-old father, Jeffrey DeWitt Osborne.
He then drove a pickup truck about 3.2 km (2 miles) to Townville Elementary School where the suspect crashed the vehicle into a fence surrounding the playground.
After the 14-year-old boy began shooting, volunteer firefighter Jamie Brock pinned him down while staff led children to safety inside the building, Anderson County emergency services director Taylor Jones said in a news conference.
Police arrived within 7 minutes of a teacher calling 911 to take the suspect into custody at the school in Anderson County, located near the Georgia state line about 160 km (100 miles) northeast of Atlanta.
The shooter never entered the building, said Chief Deputy Keith Smith.
Anderson County Sheriff's Office Captain Garland Major told reporters he did not know the relationship between the shooter and those injured at the school. The suspect was home schooled, authorities said.
"The investigation is in initial stages... it's going to be a very slow, methodical and meticulous investigation," Captain Garland Major said.
The teenage assailant was arrested without incident and has no apparent racial motivation or connections to terrorism, Major told reporters, adding that it was still unclear whether he suffers from mental illness.
The shooting left a 6-year-old boy in critical condition and undergoing surgery, Scott Stoller, Anderson County's director of emergency services, told the Anderson Independent Mail.
The other boy and a female teacher were treated and released, said Ross Norton, a spokesman for AnMed Health Medical Center. Both boys were 6 years old, the Independent Mail reported.
One male student was shot in the leg and the other boy was shot in the foot. The female teacher was shot in the shoulder, authorities said. The shooter and victims were white.
Brock, a 30-year veteran of the Townville Volunteer Fire Department, was hailed on social media as a hero and credited with preventing another school massacre.
Amazing, a volunteer firefighter can disarm and incapacitate an armed (and firing) teen... Yet police only fire killshots. #SouthCarolina— Matt Newmark (@NuConcept) September 29, 2016
Live images from the school immediately after the shooting showed a large number of police officers and members of the Anderson County Sheriff's Office heavily armed, some wearing helmets and flak jackets.
Students were evacuated on school buses to a nearby church, local media reported.
Senator Tim Scott tweeted that his heart was "sick for Anderson&South; Carolina.Praying initial reports of no loss of life remain true & for those injured and their families."
My heart is sick for Anderson&South Carolina.Praying initial reports of no loss of life remain true & for those injured and their families— Tim Scott (@SenatorTimScott) September 28, 2016
The school has almost 300 students in pre-kindergarten through sixth grade, local media reported.
School shootings have become a disturbing reality of American life and many facilities have reinforced security in recent years, especially in the wake of the Sandy Hook massacre in 2012, when 26 people — including 20 young children — were killed in Newtown, Connecticut.
The latest incident was the latest in a series of shootings at US schools that have fuelled the debate about access to guns in America.
Earlier this month, a 14-year-old girl shot and wounded a fellow student at a rural Texas high school and then died of a self-inflicted gunshot wound.