ATLANTA (CNN) -- A gunman who opened fire at a Georgia elementary school on Tuesday was armed with an AK-47 "and a number of other weapons," police said.
The shooter barricaded himself in the school's front office with employees before eventually surrendering to police, DeKalb County Police Chief Cedric Alexander told reporters.
No one was injured, authorities said. Police are investigating whether a vehicle the shooter parked outside the school contained explosives, Alexander said.
Concerns about possible explosives in the vehicle forced SWAT teams to evacuate students from the school through an escape route, Alexander said. Police cut a hole in a fence and led students through a yard to buses waiting on a nearby street, he said.
"This was a very unusual situation where we had to get the kids away from any possible explosives," Alexander said.
The shooter fired approximately six shots from inside the school toward officers as they approached outside, Alexander said, and police returned fire. The suspect is approximately 19 years old and has been detained, Alexander said. It is unclear whether he had any connection with the school.
Students from Ronald E. McNair Discovery Learning Academy, about seven miles east of downtown Atlanta, were being returned to their parents at a nearby shopping center Tuesday afternoon. The children smiled and waved and parents cheered as each school bus arrived with students aboard.
"Everybody's safe," DeKalb County Schools Superintendent Michael Thurmond said.
"This thing came out for the best," said Dale Holmes, DeKalb County's assistant police chief. "Thank God no one was hurt -- not even the suspect."
Teachers and administrators guided the students out to a lawn outside the school's gym, where they remained while investigators combed the school to make sure no other threat remained. Yellow crime scene tape marked part of a parking lot and a wall of the school.