Kashin said the S-400 surface-to-air missile has a range of 400 kilometers and defend China's entire eastern coast. The system can also be used to monitor the movement of Japanese forces over the islands, which are also claimed by Taiwan as the Diaoyutai, and attack US or Japanese aircraft or drones. Kashin believes that exporting the S-400 system to China can enhance Moscow's security ties with Beijing.
Anatoliy Serdyukov, Russia's former defense secretary, said in 2010 that the S-400 will not be sold to any foreign nations before it enters service with the Russian armed forces. Unconfirmed reports subsequently emerged that China had signed a contract with Russia to buy enough S-400 missiles to equip six air defense battalions, though these were soon denied by the Federal Military-Technical Cooperation Service of Russia, which said China and Russia were still discussing the detail of the contract.
Belarus and Kazakhstan are the only two nations that have been permitted to deploy the S-400 earlier than other nations as they share a unified air defense command with Russia and will begine to receive the systems in 2015.
In addition to enemy aircraft, the S-400 can also intercept cruise and ballistic missiles as close as 35 kilometers. Russia put it into service back in 2007.
Russian Armed Forces S-400 Mobile surface-to-air missile. Operational range 400 km.