French President Francois Hollande on Tuesday warned that "extreme horror" films used by terrorist groups could harm young people, after fresh footage emerged of Western hostages held by North African jihadists.
"Why this video?", said Hollande of the recording from Al-Qaeda in the Islamic Maghreb showing a French and a Dutch tourist they have been holding hostage for several years.
"Is it to take part in the increase in this type of extreme horror, like in Syria? Or do they want to remind us that they are detaining two people so as to emphasise their value?"
Officials said the video was likely intended as "an instrument of pressure" to force an exchange for Serge Lazarevic and Sjaak Rijke, who were kidnapped in Mali in November 2011.
The recording, confirmed as authentic by French authorities, comes as intelligence agencies are investigating the involvement of Western jihadists in the beheading of American aid worker Peter Kassig.
Hollande voiced fears about the effect "this sort of voyeurism of barbarity" could have on young people, at a time when fears are growing about Europe-born jihadists returning home from conflicts in the Middle East.
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The brutal video, released by the Islamic State group on Sunday, features two suspected French nationals among a group of men who claim to have killed 18 Syrian prisoners and the US aid worker.
Hollande said the video was an attempt to instill "horror" and send the message: "See what we are capable of and what your probable nationals are capable of."
"What is their exact role in this affair?" Hollande asked, referring to the Frenchmen seen in the video. "Are they there as killers? Or is it a signal that they are French?"
Some 1,000 French nationals are thought to have joined in the conflict, of which 375 are still there, according to Paris. At least 36 have been killed, they estimate.
Overall, 3,000 Europeans have joined the jihadists, the European Union said in September.