Russia has expanded its military operations in Syria to include a second airbase as well as other posts, according to a U.S. official briefed on the latest intelligence from the region – even as President Obama expresses muted optimism that Russian President Vladimir Putin eventually will “shift” his strategy and work with the West. 

Moscow’s presence has grown to a total of four forward operating bases, including recently added bases in Hama and Tiyas. But the most concerning to the Pentagon is the second airbase in Shayrat which can support fixed-wing aircraft, greatly expanding Russia’s capability for airstrikes, which began on Sept. 30. 

“The Russians are operating helicopters out of Shayrat airport, but they are making [preparations] to land fixed-wing aircraft,” another 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. 

Since September, Russia has based its warplanes and helicopters at Basel al-Assad airbase in Latakia, one of the last remaining Assad strongholds along the Mediterranean coast. While the Pentagon cannot confirm any Russian military jets have landed at Shayrat, there are reports Russia has landed aircraft in the past few hours. 

Russia’s two other forward operating bases are used to land its attack helicopters employed to defend the Assad regime against Syrian rebels.