The deadly Istanbul terrorist attack shows that busy international airport terminals are now a "soft target" of choice for the so-called Islamic State, a leading terrorism expert says.
And Turkey, long regarded as a bastion of security and stability on the edge of the Middle East as well as a key tourist destination for Australians visiting Gallipoli, is likely to come under increasing pressure from the militant group, analysts say.
With Turkey recently reaching out diplomatically to the Islamic State's sworn enemies Russia and Israel, the jihadist group appears to be trying to punish the country by hitting its already beleaguered tourism industry hard, experts say.
Greg Barton from Deakin University told Fairfax Media that the March attack at Brussels airport had been a "proof of concept" for the group that had been replicated in Turkey overnight.
"Brussels was hurried and messy … but it was still very effective as a kind of proof of concept to ISIL … You just go in the front door and you have made it. Airports are set up to deal with an enormous number of people. You've got globalised, international travellers at a high profile location and which is a soft target."
In the early period of the Syrian civil war, Turkey had prioritised the defeat of the regime of Bashar al-Assad and taken a tolerant view of so-called "foreign fighters" passing through its territory into Syria to join rebel groups.
But with Turkey having opened its air bases to US forces – under pressure from its NATO ally Washington – and more recently seeking to improve relations with Russia, which is strongly supporting the Assad regime, Islamic State had stepped up attacks on Turkey in an apparent bid to impose a cost on the country, said Rodger Shanahan, a former Army officer now with the Lowy Institute.
Both he and Professor Barton said that there was a still a large network of Islamic State supporters in Turkey.
President Recep Erdogan had reached out to Moscow because Russia's sanctions against Turkey in the wake of the shooting down of a Russian fighter plane last September had begun to hurt, especially in the tourism sector which relies heavily on Russian holidaymakers.
"ISIL is obviously trying to place pressure on the Turkish government," Dr Shanahan said.
Experts have long speculated that the Islamic State will increase attacks abroad as it loses territory within its so-called Caliphate across Iraq and Syria.
Dr Shanahan said the group's spokesman Abu Mohammad al-Adnani had recently called for attacks during the holy month of Ramadan, reflected in recent killings in Yemen and bombings in Lebanon.
He added that Turkish security services were stretched thin by also having to devote energy to the conflict against the Kurds in the country's east.
Professor Barton said Mr Erdogan had made the situation worse by cracking down on political opponents including clear-outs of some of the most capable intelligence and security figures in Turkey. At the same time he'd politicised Islam to bolster his own power.
"That's weakened Turkey's security situation at the very time when the problem [with Islamist terrorism] is becoming more severe," he said.
"Erdogan has been fixated on personal survival and personal power, and when someone has that tunnel vision they're bound to make mistakes and miss the bigger picture," he said.
