Relying on special police squads at major airports and bus stations and on stricter surveillance along the border with neighbouring Syria, Turkey has been stepping up efforts to prevent foreign fighters, including teenagers, from joining militant groups like the Islamic State in Iraq and Syria (ISIS).
Suspects as young as 17 have been arrested this year, in what experts and diplomats say is the result of closer co-operation between Turkish and Western security forces.
In mid-March, Turkish officers at Istanbul's Sabiha Gokcen airport stopped three British youths aged 17 to 19 after their arrival from Barcelona, Spain. Acting on a tip-off from the authorities in Britain, the Turkish officers detained the three young men after British counter-terrorism police learnt that the two 17-year-olds were on their way to join a radical group in Syria. The three teenagers were sent back to Britain.
Reports of foreigners being arrested on the Syrian border have become almost daily fare in Turkish media. In the latest cases this week, a foreigner whose nationality was withheld was arrested at the border south of the city of Gaziantep city, while a British citizen was nabbed in the border town of Kilis.
Sometimes, whole groups are caught. In April, Turkish troops near the village of Ogulpinar, just a few hundred metres from the border fence in the southern province of Hatay, picked up nine British nationals, including four children, who were trying to cross into Syria. The group included Waheed Ahmed, 21, the son of a local politician in Rochdale, north of Manchester. All were put on a plane back to Britain.
But even though Turkey has strengthened efforts to stem the flow of foreign fighters to ISIS, recruits still get through to the terror group.
In March, 18-year-old Australian Jake Bilardi, who had converted to Islam and travelled to ISIS territory via Turkey, blew himself up in a suicide van in Iraq, said news reports.
Experts fear that as the main tourist season kicks off, ISIS recruits from western Europe, posing as holidaymakers, are trying to enter Turkey.
Citizens of many European countries do not need a visa to enter Turkey, making it easy for ISIS supporters to enter the country. Some, like the 17- and 19-year-old British recruits caught in March, do not travel to Turkey directly but go to another country first to evade detection.
Visitor numbers in Turkey spike during the summer months of the northern hemisphere, especially from June to August, as millions of Europeans arrive to bask on the country's beaches or explore the cultural attractions of Istanbul and other cities.
"Numbers are rising," Mr Oytun Orhan, an analyst at the Centre for Middle Eastern Strategic Studies (Orsam), a think-tank in Ankara, told The Straits Times. "Turkey is hosting 35 million tourists a year, most of whom come from the West, so it's hard to check on everybody."
Turkey has introduced measures designed to identify potential ISIS recruits as early as possible. Controls along the Syrian border have been beefed up and, in some areas, the crossing into Syria has been made more difficult with man-made obstacles such as ditches, fences and walls.
Special police squads at major airports and overland bus stations scan arriving passengers for signs that they may be radicals. In "risk analysis centres", established at airports and bus terminals across the country last year, officers have been trying to spot extremists and deport them.
While the authorities give few details about the work of the airport squads, news reports say they have stopped about 2,000 suspects and have barred about half of them from entering the country.
Mr Orhan, the Orsam analyst, said intelligence sharing between Turkey and European countries has greatly improved since a series of deadly attacks in Paris in January. A woman thought to have been connected to one of the attackers had fled to Syria via Turkey.
"Now, we are reaping the fruits of that co-operation," said Mr Orhan about the successful identification of suspects at Turkish airports.
A Western diplomat in Ankara, speaking on condition of anonymity, confirmed that co-operation between Turkish and Western security agencies was proceeding well.
But Turkish Foreign Minister Mevlut Cavusoglu told a meeting of the Council of Europe in Brussels on May 19 that Europe "should address the root causes of radicalisation", Turkey's official Anadolu news agency reported. A Turkish diplomatic source told The Straits Times that efforts should centre on "spotting and stopping foreign fighters at their country of departure".
This article was first published on June 4, 2015.
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