13 detained over Istanbul airport attack

Istanbul

The death toll from Tuesday's gun and suicide bomb spree at Ataturk airport has risen to 42, state-run news agency Anadolu said, with 13 foreigners among the dead and more than 200 people injured.

Turkey has been plunged into mourning over the carnage at Ataturk airport, the deadliest yet of several attacks to strike Turkey's biggest city this year.

Police carried out 16 raids across Istanbul early Thursday, an official said, with three foreign nationals among the 'IS suspects' detained.

"It is probable that at least one attacker was a foreign national," he added, speaking on condition of anonymity.

Turkey has suffered a string of deadly attacks in the past year blamed on either IS or Kurdish rebels, and the airport attack comes just at the start of the crucial summer tourist season.

Interior Minister Efkan Ala told reporters late Wednesday there was an ongoing 'serious and comprehensive investigation' into who was behind the attack.

Using another name for IS, he said: "First signs point to Daesh, but it's not certain yet."

CIA director John Brennan said the attack, which has sparked international condemnation, bore the 'hallmark' of the jihadist group.

Details are emerging of how the attackers arrived at Turkey's busiest airport by taxi before indiscriminately firing at passengers with automatic rifles and detonating suicide bombs.

"The terrorists failed to pass through the regular security system, scanners and police control," Prime Minister Binali Yildirim told reporters late Wednesday.

"They returned and came back with long-range rifles they took out from their suitcases, and passed the security control by opening fire randomly at people," he said.

"One of them blew himself up outside and the other two took advantage of the panic during the opening of the fire, entered inside and blew themselves up."

A senior source close to the presidency gave a slightly different version of events, saying two attackers blew themselves up on separate floors of the airport before the third followed suit outside.

CCTV footage widely-circulated on social media showed a huge ball of flame erupting at the entrance, scattering terrified passengers.

Another video showed a black-clad attacker running inside the building before collapsing to the ground - apparently felled by a police bullet - and blowing himself up.