A former Islamic State militant captured after the fall of Raqqa says that jihadist fighters have left Syria intending to travel to Europe to launch attacks.
Saddam al-Hamadi, 26, was arrested by Turkish security forces last month after exploiting an evacuation deal designed to free civilians. He was detained as he reached the Turkey-Syria border.
But the former IS follower warned that extremists planned to use the chaos of the fall of Raqqa to travel to Europe.
"They will go overseas to launch terrorist attacks in some areas in Europe" he told ITV News in an exclusive interview granted from Turkish custody.
"They went to Europe after the withdrawal. Before that they thought the Europeans were infidels, non-believers. They will get out, across Turkey and into Europe where they will launch terrorist attacks and other things."
Saddam al-Hamadi said he had helped to smuggle new IS recruits into the group's de facto capital, Raqqa. He said that during 18 months there, many frontline roles were reserved for foreign fighters, including British recruits.
A deal between Kurdish fighters in Syria and ISIS is believed to have allowed several hundred fighters to escape the so-called caliphate and regroup.
Turkish authorities are thought to have arrested dozens of escaping IS militants caught crossing the border. An unknown number are believed to have intended to travel west before they were stopped by security forces on the Turkey-Syria border.
Saddam al-Hamadi admitting using the cover of the deal between IS and Kurdish fighters in order to escape.
"Before we left we held an agreement between Daesh (Islamic State) and the Kurdish forces. The agreement said we should leave Raqqa and go towards al-Mayadeen and return so they could take the city "
Counter-terrorism officials in London, Paris and Berlin are concerned that the collapse of Islamic State group's so-called caliphate will encourage some fighters to launch attacks in Europe.
Last month, Andrew Parker, the director-general of MI5 warned of a dramatic shift in the threat from terrorism in the UK. "It’s the highest tempo I have seen in my 34-year career" he said.
Whitehall officials believe that although few of the 850 British extremists who travelled to Syria have come back, radicalised returners are likely to present a growing threat to Britain's national security as IS territory shrinks in Syria.