(VOVworld) - Russia's deployment of its S-400 air missile defense system and ballistic Iskander missile in the Russian enclave of Kaliningrad "is destabilising to European security”, the US said as it expressed its concerns on Monday.

The S-400 is one of Russia's most modern air defence systems with an extraordinary reach. (Photo: AFP)

State Department spokesman, John Kirby told reporters that the US calls on Russia to work for regional security and stability. He added that Russia has been making threats to move its Iskander missiles to Kaliningrad for the past decade in response to a variety of developments in Europe.

Russia’s RIA Novosti news agency has quoted Viktor Ozerov, head of the defence affairs committee in the Russian parliament’s upper house, as saying that Russia has deployed more troops to Kaliningrad to increase the capability of the air force and developed state-of-the-art surface-to-air and air-to-surface missiles, capable of breaking down a US missile shield in Europe.