Russia says changes in the U.S. missile-defense posture confirm the need for "legally binding assurances" from Washington that its antimissile systems are not aimed at Russia.
The new U.S. strategy abandons plans to place long-range missile interceptors in Poland in the next decade as part of a NATO missile shield -- a step Russia had long protested.
However, the United States says it will add additional interceptors in Alaska and a radar station in Japan to counter the threat from North Korea.
Russia's Foreign Ministry said that the new U.S. installations in the Asia-Pacific region are cause for "concern."
In Brussels, NATO chief Anders Fogh Rasmussen said that "Europeans will see no difference in their missile defense" despite the U.S. change.
Based on reporting by Interfax, dpa, and AP