Russia is setting up a second airbase at Sharyat in Syria expanding the sphere of its military operations in the region to contain and destroy Isis. Russia is also putting efforts into creating strong military posts that have both offensive and defensive capabilities, according to intelligence reports emanating from the US.

Moscow's presence has now grown to a total of four forward operating bases, including recently added bases in Hama and Tiyas. But what concerns Pentagon officials is the creation of a second powerful airbase in Shayrat which can support fixed-wing aircraft, greatly expanding Russia's capability for airstrikes which began on Septtember 30, according to foxnews.com.

"The Russians are operating helicopters out of Shayrat airport, but they are making [preparations] to land fixed-wing aircraft," a U.S. official confirmed to Fox News. Shayrat is located 25 miles outside of the Syrian city of Homs, an hour drive from neighboring Lebanon.

Russia has already set up a full fledged airbase for warplanes and helicopters at Basel al-Assad in Latakia, an Assad strongholds along the Mediterranean coast. Reports say Russia has landed aircraft in the past few hours at Shayrat increasing their air force's strike power.

"This is an expansion, not a defensive move at all," the official said. He said Syrian rebels were nowhere close to taking the Russian airbase in Latakia.

Russia's two other forward operating bases are used to land its attack helicopters employed to defend the Assad regime against Syrian rebels, foxnews.com said.