From breitbart.com:
Russia’s military is ready to “neutralise” any threat to its nuclear deterrent from US missile defence sites in Europe, Deputy Foreign Minister Sergei Kislyak said Monday, according to Interfax news agency.

“If we see the development of systems that could reduce our deterrent potential, our military will have to take steps to neutralise the threat,” Kislyak was quoted as saying at a briefing in Moscow.

He did not specify the steps that would be taken, saying “this will be decided by military specialists.”

Read the article here.