Medvedev told reporters that the United States' decision to push ahead with the European shield despite Russia's objections will force Moscow "to take response measures -- something that we would very much rather not do."

"We would then be talking about developing the offensive potential of our nuclear capabilities. This would be a very bad scenario." [ yahoo ]

The Russian leader also reaffirmed any earlier threat to pull out of the new START disarmament agreement that entered into force this year if the missile shield is deployed and operated without the Kremlin's input.

"This would be a very bad scenario. It would be a scenario that throws us back into the Cold War era."