NATO has expressed concern over Russia's threat to freeze Moscow's compliance with a key arms control treaty, unless all NATO countries ratify the document.
Secretary General Jaap de Hoop Scheffer said the threat announced Thursday by Russian President Vladimir Putin was met by grave concern. He said the allies consider the Cold War-era Conventional Forces in Europe treaty one of the cornerstones of European security.
Russian Foreign Minister Sergei Lavrov defended the move. He said Moscow cannot be unconcerned by the fact that NATO military infrastructure is creeping up to Russia's borders.
He was referring to U.S. plans to deploy missiles in Poland and guidance radar in the Czech Republic.
U.S. Secretary of State Condoleezza Rice said earlier she fails to see how Russia, with its vast missile arsenal, can view 10 U.S. interceptor missiles as a threat.
The United States says the missile shield is necessary to protect U.S. interests and allies from a growing Iranian missile threat. Moscow says the system threatens its nuclear deterrent and could fuel a new arms race.
On Wednesday, U.S. Defense Secretary Robert Gates said the Russian government appears divided on how to respond to a U.S. invitation to become a partner on missile defense in Europe.
Gates said the offer included an invitation for Russian officials to visit U.S. missile sites and share data on new radar installations.
Some information for this report provided by AP, AFP and Reuters.