Shots, explosions at Istanbul airport

(Twitter)
(Twitter)

Warning: This video contains footage that may disturb some viewers. 

Three suicide bombers opened fire before blowing themselves up in the main international airport in Istanbul, killing 36 people and wounding 150, officials said.

Police fired shots to try to stop two of the attackers just before they reached a security checkpoint at the arrivals hall at Ataturk airport, Europe's third-busiest, but they detonated their explosives, one of the officials said.

Istanbul Governor Vasip Sahin said authorities believed there were three suicide bombers, an account corroborated by witnesses.

A Turkish official said the vast majority of those killed were Turkish nationals but foreigners were also among the dead.

"There was a huge explosion, extremely loud. The roof came down. Inside the airport it is terrible, you can't recognise it, the damage is big," said Ali Tekin, who was at the arrivals hall waiting for a guest when the attack took place.

A woman named Duygu, who was at passport control having just arrived from Germany, said she threw herself onto the floor with the sound of the explosion. Several witnesses also reported hearing gunfire shortly before the attacks.

"Everyone started running away. Everywhere was covered with blood and body parts. I saw bullet holes on the doors," she said outside the airport.

Footage caught on a mobile phone appears to show the chaos and capture the sound of an explosion as the blasts happened.

Warning: This video contains footage that may disturb some viewers.

There was no immediate claim of responsibility for the latest in a string of suicide bombings in Turkey this year, but the Dogan news agency said initial indications suggested Islamic State may have been responsible, citing police sources.

A Turkish official said it was too soon to assign blame.

The attack bore some similarities to a suicide bombing by Islamic State militants at Brussels airport in March which killed 16 people. A co-ordinated attack also targeted a peak-hour metro train, killing a further 16 people in the Belgian capital.

Paul Roos, 77, described seeing one of the attackers "randomly shooting" on the departures floor of the terminal.

"He was just firing at anyone coming in front of him. He was wearing all black. His face was not masked. I was 50 metres away from him," said Roos, a South African on his way back to Cape Town with his wife after a holiday in southern Turkey.

"We ducked behind a counter but I stood up and watched him.

Two explosions went off shortly after one another. By that time he had stopped shooting," Roos told Reuters.

"He turned around and started coming towards us. He was holding his gun inside his jacket. He looked around anxiously to see if anyone was going to stop him and then went down the escalator ... We heard some more gunfire and then another explosion, and then it was over."

Turkish President Tayyip Erdogan said the attack should serve as a turning point in the global fight against militant groups.

"The attack, which took place during the holy month of Ramadan, shows that terrorism strikes with no regard for faith and values," he said in a statement.

"The bombs that exploded in Istanbul today could have gone off at any airport in any city around the world," he said, urging all governments to join forces against terrorism.

Speaking in parliament earlier, Turkish Justice Minister Bekir Bozdag said initial reports suggested one attacker had initially opened fire with a Kalashnikov then detonated explosives.

Ataturk is Turkey's largest airport and a major transport hub for international travellers. Pictures posted on social media from the site showed wounded people lying on the ground inside and outside one of the terminal buildings.

A helicopter buzzed overhead as police evacuated the building. Dozens of passengers walked back down access roads with their luggage, trying to hail cabs. The US embassy urged American citizens to avoid the area.

Authorities halted the takeoff of scheduled flights from the airport and passengers were transferred to hotels, a Turkish Airlines official said. Earlier an airport official said some flights to the airport had been diverted.

The airport will be closed for up to 48 hours, Turkey told one foreign government.

AAP