Washington is investing billions of dollars to develop a missile defense system which would use rockets to shoot down hostile missiles.
It is considering placing its biggest anti-missile site outside the United States and is talking to Poland and the Czech Republic about possible locations.
"We see this as an element of destabilizing the situation, an attempt - and no more than that - to change somewhat the strategic balance," Russian Defense Minister Sergei Ivanov told a news conference.
Russia's Foreign Ministry has already said Moscow would take unspecified measures against Poland if it decides to host the anti-missile shield.