Russia has sold six battalions of S-400 surface-to-air defense missile systems to China 2501141.

The Russian Defence Ministry announced in 2011 that exports would start only after 2016, when requirements of the Russian Armed Forces are met.

Design bureau Almaz is responsible for the development of the S-400 Triumf. It is a long-to-medium-range surface-to-air missile system, designed to intercept a range of ground-based and airborne targets, such as stealth aircraft, strategic carriers and cruise and ballistic missiles at a distance of 400km.

The S-400 is code-named the SA-21 Growler. It is an upgrade of the S-300 missile system and features three different missiles, including the extremely long-range 40N6, 48N6 long-range and a 9M96 medium-range missile.

Apart from China, the system has also attracted interest from a number of foreign countries, including Saudi Arabia, Belarus, and Turkey.

Russia plans to buy up to 200 launchers (each with two or four missiles) by 2015, and phase out the older S-300 and S-200 systems. This would mean deploying at least 18 battalions by 2017 and 56 by 2020 (or organized into 28 battalions containing two battalions each).

China plans to deploy its first S-400 battalion opposite Taiwan. That one battalion can cover all Taiwanese air space. The next battalions will be deployed to deal with Japan, South Korea and Vietnam.