Relatives of one of the victims of yesterday's blast at Istanbul Ataturk Airport mourn in front of a morgue in Istanbul, Turkey, June 29, 2016.

Around 20 Islamic State militants, mainly foreigners, are in custody in connection with an attack last week on Istanbul airport that killed 45 people, Turkish President Tayyip Erdogan said on Saturday.

Two Russian nationals have been identified as suspected Islamic State suicide bombers in the attack that is thought to have been masterminded by a Chechen, Turkish media said on Friday.

"The latest findings point to the Daesh (Islamic State) terrorist organisation," Erdogan told Reuters at the Istanbul Ataturk airport, where he visited the attack site.