Opening day at Six Flags Over Georgia turned into mayhem after 500 or 600 teens started brawling. A smaller group of teens allegedly started shooting at cops. (WAGA/YouTube)

Police got into a shootout with several teenagers just outside a Six Flags on Saturday night, injuring a 15-year-old boy.

It happened just after 6 p.m. at the Six Flags Over Georgia in Cobb County. Authorities say about 500 or 600 teenagers began running through the park and brawling near the entrance. Security and Cobb County Police began clearing out the park when a group of teenagers fired shots at cops on a street just outside park property, the Georgia Bureau of Investigation said in a press release. No officers were hit but a bullet struck an unoccupied Cobb County police car.