Russian troops have begun to aid military operations inside Syria, in an increase in efforts to back Syrian President Bashar al Assad’s forces, according to reports made by three Lebanese sources familiar with the political and military situation in the region on Wednesday.
The US fears that this action indicates deepening Russian military influence in Syria's four-year conflict, though one of the Lebanese sources, speaking to Reuters on condition should they not be identified, reported that the number of Russian forces deployed into Syria so far was small.
In the past day or two, Russia has sent two tank landing ships and an additional cargo aircraft to Syria, including the deployment of a small number of naval infantry forces, according to reports given by US officials, who also spoke on condition they not be identified.
They added that the intent of Russia's military advances into Syria was still unclear, but one possible reason could be to prepare an airfield near the port city of Latakia, which is currently a stronghold of Assad forces.
However, the officials have not ruled out the possibility that Russia may want to use the airspace for air combat operations.
NATO chief Jens Stoltenberg stated that if Russia is deploying its army into Syria, then Moscow's involvement would not help put an end to the conflict that killed more than 200,000 people and displaced more than 10 million people inside and outside the country.
Separately on Wednesday, US Secretary of State John Kerry reiterated his concerns to Russian Foreign Minister Sergei Lavrov over the phone, warning that such advances could fan more violence.
Russia, a key ally of Assad during the country’s four-year crisis, stated that it has sent military experts but that is all.
A Russian foreign ministry spokeswoman, Maria Zakharova, insisted on Wednesday that this operation was nothing new, arguing that Moscow had been openly supplying weapons and sending military specialists to Syria for a long time.
"Russia has never made a secret of its military-technical cooperation with Syria,'' Zakharova said.
Assad’s government has also denied any military advances by Russian troops on Syrian soil.
Moscow has stated repeatedly that Assad’s government must be incorporated into the shared international battle against ISIS, which has taken over large parts of Syria and Iraq, even though the US and Assad's regional enemies view him and his regime as part of the problem.
"We would welcome constructive Russian contributions to the counter-ISIS effort, but we've been clear that it would be unconscionable for any party, including the Russians, to provide any support to the Assad regime," White House spokesman Eric Schultz said.
US officials say that Russia’s increase in military assistance to Assad forces may be due to this year’s substantial territorial losses to ISIS militants, who have come to be seen as the bigger threat.