Turkish President Tayyip Erdogan (front second left) is accompanied by Sani Sener (left), chief executive of Turkish airport operator TAV, and Istanbul Gov. Vasip Sahin (front second right) during his visit at Ataturk airport in Istanbul, July 2, 2016. Murat Cetinmuhurdar/Presidential Palace/Handout via REUTERS

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.