Russia has deployed one S-300 anti-aircraft missile system at its military base in Tajikistan.

Citing the press center of the Russian Central Military District, Kommersant says the system has been delivered to Tajikistan from Volga region by rail.

RBC news agency, citing a source close to the Russian Ministry of Defense, says the missile system will be deployed at the border with Afghanistan.

According to the source, the S-300 will be deployed in Tajikistan to provide air defense of the Russian 201st military base.

The S-300 is a series of initially Soviet and later Russian long range surface-to-air missile systems produced by NPO Almaz, based on the initial S-300P version.  The S-300 system was developed to defend against aircraft and cruise missiles for the Soviet Air Defense Forces.  Subsequent variations were developed to intercept ballistic missiles.  The system is fully automated, though manual observation and operation are also possible.  Components may be near the central command post, or as distant as 40 km.  Each radar provides target designation for the central command post.  The S-300 is regarded as one of the most potent anti-aircraft missile systems currently fielded.

The Russian military base deployed in Tajikistan is Russia's largest non-naval military facility outside the country.  It was officially opened in Tajikistan in 2004 under a previous agreement, which was signed in 1993, and hosts Russia’s largest military contingent deployed abroad.

A total of some 7,000 Russian troops are now stationed at two military facilities collectively known as the 201st military base - in Dushanbe and Bokhtar (formerly Qurghon Teppa, some 100 kilometers from Dushanbe.