"The military could consider action to counter the missile defence. That includes Iskander missile systems and strategic bombers in Belarus and Kaliningrad,'' Surikov said.

Kaliningrad is a Russian enclave situated between Poland and Lithuania.

Belarus, an ally and neighbour of Russia, handed over its Soviet-era nuclear arsenal to Mosocw in the early 1990s.

Surikov's warning echoed one from a Russian general who said last November that Iskander missiles could be sent to Belarus.

Placing such missiles in Belarus, which borders Poland, would put the planned US missile defences there within firing range, although the site in the Czech Republic is likely to be out of reach.

Iskander missiles can be fitted with conventional or nuclear warheads, and Russian strategic bombers can also be equipped to carry conventional weapons.

The Kremlin has rejected US assurances that the sites are intended to fend off missile threats from Iran, saying they will threaten Russia's nuclear deterrent.