Russia has sent some of its most modern battle tanks, moving forward with its plans on establishing a new air base in Syria, the Pentagon said on Monday.

A Russian ‘intervention’ in Syria? 

Russia has been actively supporting President Assad since the beginning of the Syrian civil war, in which at least 240,000 people were killed and millions displaced. Russia has been providing both logistical and political support. Syria – or what remains of it – is Russia’s main strategic foothold in the Middle East, an asset Moscow wants to defend.

Since 2011, a swath of country has fallen under the control of IS. Russia has been fearing the spillover of Islamic State – with many of its citizens leaving to Syria and Iraq to fight in the civil war – onto its own soil. Combating jihadi fighters is a key priority on in its security agenda. Kremlin continues to believe that the fall of Assad’s regime will lead to further radicalization in the Middle East and spillover of Islamic radicalism to the North Caucasus, Russia and Central Asia. It is thus not a surprise that Russia is highly interested in Assad’s regime staying in power.

In recent days and weeks, Russia has increased its support for the regime and reportedly provided advanced operational equipment and weaponry. Pentagon’s spokesperson, Jeff Davis, told journalists on Monday:

We have seen movement of people and things that would suggest the air base south of Latakia could be used as a forward air operating base.

This move can further complicate the US and coalition efforts to mount daily airstrike against Islamic State militants.

Meanwhile, Russia has also positioned half a dozen of tanks and other equipment to the Syrian airbase in Latakia, two US officials told to Reuters news agency on Monday. They added that the intentions of the Kremlin’s latest deployment of heavy artillery is unclear. Moreover, one of the US officials, who spoke to Reuters on condition of anonymity, said seven Russian T-90 tanks arrived in Latakia in the past few days but had not been seen outside the airbase. The artillery was likely for airfield defense, the source tells.

The latest consignment were said to include surveillance drones and other advanced artillery.  But the US has not yet seen any fighter jets or attack helicopters arrive, Davis told journalists. It is clear that the Kremlin has stepped up its military assistance to Syria. Moscow has no intention of withdrawing its support from Assad.

‘No additional steps’ 

Although photographs, reports and social media posts suggest that Russian soldiers are in Syria, the Kremlin has maintained that they are there as advisers. Pentagon’s spokesperson has expressed his concerns that the Russian military activity could conflict with the US-led coalition’s airstrikes against Islamic State.  He added that Washington would welcome Russian efforts in combating militant Islamist, but the military assistance for Assad “are unhelpful and risk adding greater instability to an already unstable situation.”

The US comments come just days after the Syrian state media reported that two Russian cargo planes landed with 80 tonnes of humanitarian aid. The planes have reportedly flown into Latakia on Saturday. Russian Defense Ministry spokesperson Igor Konashenkov said the plane was carrying materials for setting up refugee camps.

The Kremlin has dismissed any military built up, although Russia’s Foreign Minister Sergei Lavrov said last week that Russia will send more help to Syria. In an interview on a Russian television new program on September 14, Lavrov said: 

Russia is sending planes to Syria with both military equipment in accordance with current contracts and humanitarian aid. Russia is not taking any additional steps.

Russian officials have not commented on the alleged arrival of military artillery in Syria. But the Syrian ambassador to Moscow, Riad Haddad, denied on Monday that Moscow was conducting a military build up in his country, calling news of a Russian troop presence a ‘lie’. He said Syria was receiving military equipment from its ally under the defense contracts.

Growing suspicion in the West

The US-based intelligence-gathering company Statfor published satellite imagery last week of construction on the Bassel al-Assad international airport in Latakia, Syria. According to the company, this is evidence of the Russian military “establishing a base operations” and preparing to deploy aircraft to Syria, if it has not already done so.

Suspicions about Russia’s activities in Syria are growing. Last week, Bulgaria closed its airspace at the US request to the Russian flights, amid fears that Russia is boosting its military support to Syria. The Bulgarian authorities suspected that the aircraft were not carrying aid, as claimed by the Russians. Meanwhile, President Barack Obama warned Russia that it was making a mistake by aiding Assad.

Nevertheless, efforts to stop the flow of supplies have fallen short. Russia is ignoring warnings from the United States and the West, flying its military assets through Iran.

“I don’t believe Western governments are prepared to do very much to slow down or block the risky course the Russians are going on,” said Andrew S. Weiss, a former Russia expert for the Pentagon, Vice President for studies at the Carnegie Endowment for International Peace told New York Times.

The rise of Islamic State over the past years has been a concern for both Russia and the West. However, the US coalition to strike IS has come in spite of Assad, whose removal remains a US foreign policy objective and a major point of contention with Moscow.