Paris:

Most of the ex-soldiers, reportedly numbering around 10 and including former paratroopers and French foreign legionnaires, are said to be fighting on behalf of the Islamic State.

Islamic State image from a propaganda video.

Most worrying is the reported presence of an ex-member of France's elite First Marine Infantry Parachute Regiment, considered one of Europe's most experienced special forces units and which shares the "Who Dares Wins" motto of the SAS.

The unnamed individual, of North African origin, had received commando training in combat, shooting and survival techniques. He served for five years before joining a private security company for which he worked in the Arabian peninsula, where he was radicalised before heading for Syria, according to L'Opinion, a news website.