REPUBLIKA.CO.ID, ISTANBUL -- All three suicide bombers in an attack on Istanbul's main airport on Tuesday opened fire before blowing themselves up, according to initial findings, Turkish Prime Minister Binali Yildirim said.

Yildirim also told reporters at the airport that there were likely to be foreigners among the 36 people killed.

There was no immediate claim of responsibility for the attack, the latest in a string of suicide bombings 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 coordinated attack also targeted a rush-hour metro train, killing a further 16 people in the Belgian capital.