The threat followed quickly on from the announcement that Condoleezza Rice signed a formal agreement with the Czech Republic to host the radar for the controversial project.
Moscow argues that the missile shield would severely undermine the balance of European security and regards the proposed missile shield based in two former Communist countries as a hostile move.
“We will be forced to react not with diplomatic, but with military-technical methods,” the Russian Foreign Ministry said in a statement.
The ministry did not detail what its response might entail.
Dr Rice, the US Secretary of State, hailed the agreement as a step forward for international security.
After 14 months of negotiations, the US is struggling to clinch agreement with its other proposed partner - Poland - where it hopes to locate the interceptor missiles designed to shoot down any incoming rockets.
Russia threatens military response to US missile defence deal - Times Online