A US intelligence official has revealed the airstrikes have seen results against terror.
He told Reuters: "The Russians did not go blindly into this, they are getting some advantage out of the price."
According to the Kremlin, in spite of carrying out more than 5,000 airstrikes since the beginning of the campaign, Russian troops have suffered only a small number of casualties.
Financially, the military operation also seems to be working out for Moscow.
Russia has an annual defence budget of $54billion, but country officials say sending military jets to Syria is costing a relatively modest one to two billion dollars per year.
However, experts say Russia's military success against ISIS in Syria also means groups opposed to the Syrian President Bashar al-Assad have been weakened.
Since the start of Syria's civil war in 2011, Russian President Vladimir Putin has been Assad's closest ally. Both leaders have vowed to, together, defeat ISIS, which now controls vast swathes of Syrian territory.
Russia is now one of a number of foreign armies conducting military operations in Syria, as world powers rush to obliterate ISIS in the wake of last month's Paris terror attacks which killed 130 people.
According to figures provided by the New York-based Soufan Group, there are now many nationals fighting alongside ISIS in Iraq and Syria. Saudi Arabia and Tunisia also rank high on the list, with 2,500 and 3,000 of its citizens, respectively, fighting for the terrorist group,Express reported.
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