The first S-400 regiment has been deployed in Electrostal, also near Moscow, as part of the air and missile defense network around the Russian capital.
The S-400 (SA-21 Growler) air defense system is expected to form the cornerstone of Russia's theater air and missile defenses by 2020.
The S-400 system can engage targets at a maximum range of up to 400 km at an altitude of 40,000-50,000 meters. The system uses a range of missiles, optimized for engaging ballistic and cruise missiles.
An S-400 air defense regiment consists of two or three battalions equipped with four systems each. Russia is planning to arm 56 battalions with S-400 systems by 2020.