Russia’s Defense Ministry said Tuesday that it had sent an S-300 missile system to its naval facility in the Syrian city of Tartus, a measure it says is meant to bolster its security.

“The S-300 anti-aircraft missile system has indeed been sent to the Syrian Arab Republic,” Defense Ministry spokesman Major General Igor Konashenkov said in a statement.

Konashenkov made the statement after US news station Fox News said Russia has deployed an advanced anti-missile system in Syria for the first time, citing three US officials.

“Let me remind you that the S-300 is a purely defensive system and poses no threat to anyone. It is unclear why the deployment of the S-300 caused such alarm among our Western partners, Konashenkov said.

He noted that the system was similar to one earlier deployed at sea on the cruiser Moskva.

The officials said the new weapon system could potentially counter any US cruise missile attack in Syria, in a latest show for Russian military support to Syrian President Bashar al-Assad.

The deployment of the S-300 surface-to-air missiles (known to NATO as the SA-23) to Russia’s naval base at Tartus is the first time Russia has deployed the system outside its own territory. It joins another sophisticated anti-aircraft system, the S-400, already in place at the Russian air base near Latakia.

The S-300 is highly mobile - its radars, launchers and command systems carried on a number of vehicles. It can be mounted on a heavy wheeled launcher as well.

It is one of the most lethal area defense systems ever developed intended to engage aircraft, cruise and ballistic missiles.

Its deployment indicates that Russia is significantly bolstering its air defenses in Syria. This is a clear signal to Washington that there would be a heavy price to pay should the US be tempted to intervene in some way against Russian or Syrian operations.

Fox News reported earlier quoting unnamed US officials that the system had been deployed at the weekend.

In addition to the Tartus naval base, Russia uses the Hmeimim air base near the Syrian coastal city of Latakia.

Last year, Moscow deployed the more advanced S-400 system there as it began conducting air strikes in Syria. 

File Photo: A Russian air defense missile system Antey 2500, or S-300 VM, is on display at the opening of the MAKS Air Show in Zhukovsky outside Moscow on August 27, 2016.