French authorities have accused a Senegal-born French national of being the main recruiter of fighters from the country to Syria's civil war, which he claims to have done using online platforms.

In a tape obtained exclusively by Al Jazeera, 39-year-old Omar al-Diaby, better known as Omar Omsen, says that he initially used the internet to reach out to potential recruits whom he convinced that travelling to Syria amounted to migrating to the "land of Islam".

The revelations come amid a UN warning that the conflicts in Syria and Iraq are attracting foreigners on an unprecedented scale.

Omar al-Diaby, better known as Omar Omsen, has never revealed his face before on camera [Al Jazeera]

"I don't have time to be on Facebook any more. But this is how at first I was encouraging people to do the 'hijra', to leave France and western countries to come here," said Omsen, who is believed to be based in the Syrian-controlled Latakia countryside.

"God asked to encourage the faithful to fight. So we are encouraging them, and we're letting them know that 'hijra' is compulsory for them, and that living in western countries is forbidden. The prophet is clear on that subject. A Muslim can't live among the infidels."

It is unclear how a man who is not a Muslim religious figure and was jailed in France on criminal charges was able to gain popularity online.

He uploads videos to a YouTube page but has never revealed his face before.

Online presence

David Thomson, author of Les Francais Jihadistes  (The French Jihadists), told Al Jazeera that Omsen gained popularity through his online presence.

"His videos are very basic with old archives from films of newsreels in France that call for jihad abroad, but they have had a big impact on young people in France, many of whom went to Syria," Thomson said.

"That is what has given Omar his legitimacy."

Foreign fighters join Syria's rebels - A 2012 report by Al Jazeera's Zeina Khodr from Aleppo

Thomson said Omsen's group is now attracting fewer fighters as he has less presence online.

"They are quite isolated with very young followers," he said. "They also fight very little."

Currently most of the recruiting to the war-torn region is being done by the Islamic State of Iraq and the Levant (ISIL) armed group, and several French nationals have appeared in its propaganda videos also distributed online.

But Omsen says that he does not recruit fighters to join a specific group but rather to join a cause.

"For the time being, we are not following them [ISIL]. We are hearing things about what Dawlat [ISIL] is doing, and what Jabhat [Nusra Front] is doing. So we're taking our time to look and see," he said.

"We did not come here to get killed by a Muslim bullet or shoot at Muslim people. We came here only because of God's enemy, Bashar al-Assad."

The US Central Intelligence Agency says there could be anywhere between 20,000 and 31,500 fighters in Iraq and Syria. About half of them are believed to be foreigners from over 80 countries.

France says at least 1,000 of its citizens have left or plan to leave the country to join ISIL.

Anne Giudicelli, founder of the Paris-based consulting group TERRORISC, which specialises in risk analysis, told Al Jazeera that France has installed programmes to prevent these fighters from bringing the fight back home, if they choose to return.

"There's still the possibility [of an attack] because the more you fight against these groups, the more determination and willingness they will have to attack not only France, but also other European interests," she said.

Source: Al Jazeera