Professor Jytte Klausen, who teaches at Harvard and Brandeis Universities, and is the founder of the Western Jihadism Project, described how a list of 10,000 names of suspected IS sympathisers to watch for was given to the Turkish authorities by EU countries.
Her comments come as three British teenagers were detained by officials in the country as they tried to travel to Syria.
She said: “The Turks complained that they can’t do it, and you know what, they can’t. It’s a capacity busting proposition, to watch out for 10,000 westerners. They are not going to be able to check most names on that list of 10,000. Only if there is a case where there is an urgent bulletin out, because it has been discovered that they had left — and the urgent bulletin would be on the top of the desk — that’s when you can catch people as happened here.”
The three teenagers, a 19-year-old and two 17-year-olds, were arrested on suspicion of preparing terrorist acts after returning to the UK, police said.