Dmitry Medvedev accuses Washington and Nato of ignoring Moscow's concern at defences they say are aimed at Iran
Russia has threatened to deploy missiles to target the US missile shield in Europe if Washington fails to assuage Moscow's concerns about its plans.
The harsh warning reflects deep cracks in US-Russian ties despite Barack Obama's efforts to "reset" relations with the Kremlin.
President Dmitry Medvedev said on Wednesday that he still hopes for a deal with the US on missile defence, but he accused Washington and its Nato allies of ignoring Russia's worries. He said Russia will have to take military countermeasures if the US continues to build the shield without legal guarantees that it will not be aimed against Russia. More