“New challenges emerge, including missile and nuclear proliferation. Look at how unstable the situation in the Middle East is. That’s why Russia’s military doctrine envisages the use of nuclear weapons in specific cases. I do not rule out than under certain circumstances we will have to boost, not cut, our nuclear arsenal,” Antonov said in an interview with the Kommersant daily.

He named the U.S. missile shield in Europe as a main threat to Russia’s security.

"The situation is dismal in this area. The U.S. continues to boost is missile defense potential in Europe and other regions. The European segment of the U.S. missile defense demonstrates aspirations to shift the strategic balance of forces in Europe. After the Cold War, U.S. strategic weapons - and missile defense is a strategic weapon - are getting closer to Russia’s borders,” Antonov said.

He also confirmed that Russian and U.S. missile defense talks have reached deadlock as U.S. cooperation proposals are vague and Russia’s participation in the project “is not even up for discussion.”

The deputy defense minister reiterated that Russia may quit the Russian-U.S. treaty on strategic arms reduction, signed in 2010.

“This is one of possible variants of our retaliation measures. We have warned about it beforehand,” he said.