Moscow - Russian President Vladimir Putin on Thursday said Moscow had made the key contribution to defeating the Islamic State group in Syria, adding its military campaign also boosted morale in the armed forces.

Russia "has made the principal, decisive contribution defeating the criminal force which challenged our entire civilisation," Putin said at a ceremony to award officers who took part in Moscow's Syria campaign.

He called the jihadists a "barbaric dictatorship which sowed death and destruction" and accused them of "global aggression, the target of which is and was our country."

In a speech before the hundreds of servicemen in the Kremlin, Putin said Russia's intervention in Syria had also changed the armed forces as it boosted confidence and showed off Moscow's military might to the world.

He said some 48 000 Russian servicemen took part in the campaign, which Russia launched in September 2015 in support of Syrian President Bashar al-Assad, helping turn around the multi-front war.

"You as no one else understand, know and feel that the army has drastically changed over these two-something years," he said.

"It changed because people felt they were at their best."

"They understood how our military equipment works, how our command and supply works, how modern our armed forces have become. The whole world saw this, and most importantly, our people too."

Putin earlier this month made a surprise visit to Russia's Hmeimim airbase in Syria where he ordered a partial pullout of the country's troops, saying their task had been largely completed.

Russia said the Hmeimim airbase in Latakia would remain in operation, while its naval facility in the Syrian port of Tartus would be expanded.