Up to three attackers were involved, with one reportedly opening fire with a Kalashnikov as they targeted an entry point to the terminal.
Recent bombings in Turkey have been linked to either Kurdish separatists or the so-called Islamic State group. Tuesday’s airport attack looks like a major, co-ordinated assault, says the BBC’s Mark Lowen at the scene.
Ataturk airport was long seen as a vulnerable target, our correspondent says. There are X-ray scanners at the entry to the terminal but security checks for cars are limited.
‘Armed with a Kalashnikov’
Flights in and out of the airport were suspended after the attack. Taxis were used to rush casualties to hospital in the immediate aftermath of the attack. The state-run Anadolu agency said around 60 people had been wounded, six of them seriously.