Three male British teenagers planning to join Islamic State militants in Syria have been detained in the Turkish city of Istanbul, Turkish and British officials said on Sunday.
The three, who have not been named, were detained on Friday, Turkish sources said, after a tip-off from British authorities that two of them were travelling to Turkey via Spain.
Their detention comes after three British schoolgirls entered Turkey last month and are thought to have joined Islamic State in Syria.
Police in London said they had been made aware that two 17-year-old boys had gone missing and were thought to be travelling to Syria. Further inquiries revealed they had travelled with a 19-year-old male, police said.
“Officers alerted the Turkish authorities who were able to intercept all three males, preventing travel to Syria. They remain in detention in Turkey. The families have been kept informed of developments,” the police statement said.
Security services estimate some 600 Britons have gone to Syria or Iraq to join militant groups, including the man known as “Jihadi John” who has appeared in several Islamic State beheading videos.
Hundreds of other Europeans have also joined the fight.
Their involvement has raised fears about the possibility of attacks at home if they return trained and further radicalised.
Turkey meanwhile has faced criticism for not better controlling its south-eastern borders, and has accused European countries of failing to prevent would-be jihadists from travelling in the first place.
Arrangements were being made with British authorities to deport the males this week, a senior Turkish official, who spoke on condition of anonymity, said.
On Thursday, the Turkish foreign minister said the girls who had earlier travelled to Syria had been helped to cross the border by a spy working for one of the countries in the U.S.-led coalition against the militants.
Islamic State controls swathes of territory in Syria and Iraq where it has declared an Islamic caliphate.