Leaked IS documents to be used in French trial

French prosecutors will use leaked Islamic State documents to help identify seven suspected militants going on trial next week, including the brother of a Paris attacker, sources close to the investigation said on Wednesday.

The seven men from Strasbourg in eastern France, aged between 24 and 26, are accused of travelling to join the Islamic State group (IS) in Syria in late 2013 and returning several months later.

Among the men, who were arrested in May 2014, is Karim Mohamed-Aggad, brother of Foued Mohamed-Aggad who was part of the three-man group that attacked the Bataclan concert hall on the night of the Paris attacks in November.

The Paris prosecutor's office intends to use the documents, acquired by British TV station Sky News in March, during the trial that starts on Monday, but the move has been criticised by the defence lawyers.

"Five days from the trial, this is an unusual step," said one of the defence lawyers, Eric Plouvier, saying there were doubts over the authenticity of the IS documents.

"Either these elements should be removed, or there should be a report to study (their authenticity)," he said.

The documents contain some 22,000 names of individuals linked to IS in 2013 and early 2014, the investigation source said.

An estimated 173 of those names are French citizens or residents of France, including several who have died in Syria and Iraq and two more of the Paris attackers - Samy Amimour and Omar Ismail Mostefai.

The documents, written in Arabic under the title "General Border Administration", log the name, blood type, date of birth, previous job, level of religious education and more of each new arrival to the IS zone of control.

They are also listed as "combatant", "martyr" or "Inghimasi", a term referring to fighters who carry weapons as well as an explosive suicide vest.

The documents list the seven men from Strasbourg as "combatants".

However, all seven claim to have travelled to Syria for humanitarian reasons.