Image copyright Reuters Image caption Airport security failed to trace the man who fled the scene
At least two people were killed and nearly 90 injured after a man with a firearm brought an unsecured gun through security at Atlanta’s Hartsfield-Jackson International Airport.
Pictures of the scene showed bodies lying on the floor after the gun went off.
Police said two victims died at the scene, and it is believed that a third died after a hospital visit.
Four others were taken to hospital in a critical condition, and a further 26 suffered minor injuries.
In a statement, police said the shooter, who fled on foot after the incident, was in his late 20s and had been on previous runs-ins with law enforcement.
Officers said they were searching for a man described as 5ft 6in to 5ft 8in tall, with a slender build and brown hair.
Image copyright Twitter Image caption A suspect has not been found, but police are looking for a man described as being 5ft 6in to 5ft 8in tall and with a slim build
Atlanta police chief George Turner said officers had chased the man, but were not able to apprehend him, and offered an apology to the airport staff.
“We don’t want anyone to have to go through that traumatic experience. It’s hard to find the words to say”, Chief Turner said, shortly after a briefing.
Images and video showed a pool of blood on the floor of Terminal 2 in the aftermath of the incident.
“There were people trampling over each other and running into each other,” an eyewitness told CNN, saying that the hotel to the airport was being evacuated.
Image copyright Reuters Image caption The gunman, who is in his late 20s, is believed to have slipped through security
Image copyright Twitter Image caption A picture of the scene showed a pool of blood on the floor after the gun went off
Mr Turner said a total of 2,017 passengers had been trapped in their flights or evacuated by personnel.
Hundreds were asked to leave their planes at the tarmac, the FBI tweeted, while an investigation is being carried out at the scene.
Traffic was diverted to neighbouring Centennial Olympic Park, to avoid the airport.