The Russian government is allegedly secretly paying young men to fight extremists in Syria, despite the Kremlin's repeated claims that the country's involvement in the war is strictly aerial, according to one report.

On Wednesday, Britain-based Sky News reported that a private military company called 'Wagner' — illegal under the Russian constitution — has been recruiting hundreds of men and flying them down to Syria on Russian military transport planes.

The two men interviewed by Sky News, whose names have been changed to Dmitry and Alexander, claim they were paid the equivalent of $3,900 a month to fight against rebel factions, including the Islamic State. This, despite Russia's claims the only people it has on the ground are instructors and military advisors, and Prime Minister Dmitry Medvedev telling a German newspaper in February that the presence of foreign powers in Syria could unleash a world war.

Dmitry told Sky News that about 500 to 600 Russians have died in Syria, which stands in stark contrast to the official Russian casualty count of 19.

Wagner is headed by a former special forces soldier known as Nikolai Utkin, who has been described in Russian media as an admirer of the Nazi German Third Reich, with 'Wagner' being an homage to Adolf Hitler's favorite composer, Sky News reported.

The company allegedly recruits men online through military-themed chatrooms. In a record of one such conversation obtained by Sky News, a man reaches out to Wagner and answers a few basic questions about his physical fitness and any potential legal issues before being asked to "come to Molkino," a small town that's home to a special forces base.

According to Alexander, Wagner isn't highly selective when it comes to recruits, but the training, which lasts for a month or two, is intense, and how the men end up serving depends on their level of military experience.

The two men said authorities are covering up the deaths by reporting the men as missing, or having their records say they died elsewhere.

Dmitry, who is now back in Moscow and says he's one of about 50 former Wagner troops in the city, gave up his personal identification when he signed up to serve. When he returned from Syria and went to the training base to get it back, he was arrested and told that Wagner doesn't exist.

If the accounts are true, this wouldn't be the first time Russia has understated its on-the-ground participation in a conflict. Last year, the Atlantic Council found evidence of Russia's presence in Ukraine using open source information and social media, despite President Vladimir Putin's denials. VICE News then used the same methodology to track one Russian soldier from eastern Ukraine to Siberia, confirming Russia's involvement.

Follow Tamara Khandaker on Twitter: @anima_tk