There are about 200 Russians currently fighting alongside rebels battling the Syrian regime, the head of Russia's Federal Security Service (FSB) said.

It is the first confirmation by Moscow that Russian-born Islamists are active in the Syrian civil war, and contradicts some earlier denials of their involvement by Russian officials.

"There is great concern in Russia that there are about 200 militants from the Russian Federation fighting [in North Africa and Syria] on the side of the Caucasus Emirate [militant Islamic organization] under the flag of Al Qaeda and other affiliated structures," FSB head Alexander Bortnikov said at an international security conference.

Most Russians fighting against the government of Syrian President Bashar Assad are believed to come from the North Caucasus, which has a thriving jihadist movement - the legacy of a series of brutal separatist wars following the fall of the Soviet Union.

The Kremlin is particular concerned about instability in the North Caucasus ahead of the 2014 Sochi Winter Olympics, which could be fuelled by hardened fighters of Russian origin leaving Syria to go home. Sochi is a Russian Black Sea resort located in the vicinity of the volatile North Caucasus region.

"This is a very serious threat for all states, for Russia and CIS countries and for European states and the American continent," said Bortnikov. "The danger is that these terrorists will end up returning to the country from which they left."

Russian officials have previously downplayed the role played by Russian militants in Syria. Chechen leader Ramzan Kadyrov said last year that it was a "hoax" to suggest Chechens were among the Syrian rebels.

But evidence of Russian involvement with the rebel movement has grown as Syria`s bloody civil war continues.

Russia`s most wanted man, rebel leader Doku Umarov, who is also the head of the Al Qaeda-linked Caucasus Emirate, appeared in a video last year saying that those fighting against Damascus were in his prayers.

And a Russian-language website, Fisyria.com, was launched in March by a Syrian rebel group called Jaish al-Muhajireen wa Ansar (`Army of the Emigrants and Helpers`).

While Assad's government is dominated by Shia Muslims, the prevalent form of Islam in both the North Caucasus and amongst the Syrian rebels is Sunni Islam.

Source: ANTARA