Russian forces have begun participating in military operations in Syria in support of government troops, three Lebanese sources familiar with the political and military situation there said on Wednesday. …

Two U.S. officials said Russia has sent two tank landing ships and additional aircraft to Syria in the past day or so and has deployed a small number of naval infantry forces….

Moscow confirmed it had “experts” on the ground.

But Russia has declined to comment on the exact scale and scope of its military presence in Syria. Damascus denied Russians were involved in combat, but a Syrian official said the presence of experts had increased in the past year….

Two of the Lebanese sources said the Russians were establishing two bases in Syria, one near the coast and one further inland which would be an operations base.

“The Russians are no longer just advisors,” one of them said. “The Russians have decided to join the war against terrorism.”

Another of the Lebanese sources said that so far any Russian combat role was still small: “They have started in small numbers, but the bigger force did not yet take part …

There are numbers of Russians taking part in Syria but they did not yet join the fight against terrorism strongly.”

The Syrian official said: “Russian experts are always present but in the last year they have been present to a greater degree….”

NATO Secretary General Jens Stoltenberg said reports of growing Russian military activity in Syria were a cause for concern, while France said it made finding a political solution to the crisis more complicated….

A senior U.S. official said on Saturday Washington had detected “worrisome preparatory steps,” including transport of prefabricated housing units for hundreds of people to a Syrian airfield, that could signal that Russia is readying deployment of heavy military assets there.

Image: Syrian President Bashar Assad and Russian President Vladimir Putin, Jan. 25, 2005 (photo: Office of the President of Russia)