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 ex-ISIS fighter has warned that extremists planned to use the chaos of the fall of Raqqa to travel to Europe.

A threat issued by Islamic State on its channels showing a bloodied knife with the Eiffel Tower and a Christmas market in the background and the caption, 'Soon in your holidays'

Talking to ITV while in Turkish custody, Al-Hamadi said: 'They will go overseas to launch terrorist attacks in some areas in Europe.

'They went to Europe after the withdrawal. Before that they thought the Europeans were infidels, non-believers.

A Russian spy is executed by a terrorist in front of an ISIS flag

'They will get out, across Turkey and into Europe where they will launch terrorist attacks and other things.'

The alleged terrorist said he had helped to smuggle new ISIS recruits into the group's de facto capital, Raqqa.

He said that during eighteen months there, many frontline roles were reserved for foreign fighters, including British recruits.

'I used to receive people from outside Raqqa - from Idlib and other places.

'We would wait for them at night and smuggle them inside. They would be trained in military courses and religious courses in the centres.'

He claims to have used his knowledge of smuggling routes into ISIS territory to find a way out.

Al-Hamadi told Turkish interrogators that he was attempting to get to Europe to earn a living for his family in Syria, not to commits acts of terrorism.

A judge is due to hear his case this week.

ISIS fighters in convoy. Militants are said to be flooding out of Syria and Iraq as the terror group collapses

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 800 British extremists who travelled to Syria have come back, radicalised returners are likely to present a growing threat to Britain's national security as ISIS territory shrinks in Syria.