President Vladimir Putin said on Friday that Russia had nuclear warheads that could penetrate any missile defense system, NBC News reported.
"We've advanced in improving the systems ... including [those that have] to do with overcoming missile defenses," he said during his annual press conference in Moscow. "Today, this system is more efficient than the [U.S.] missile defense."
"It's not us who have been speeding up the arms race," Putin also said.
On Thursday, President-elect Donald Trump stunned nuclear experts when he said "the United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes."