Russia is rejecting U.S. accusations it has broken any of its nuclear treaty obligations, arguing it wants only to maintain global peace and stability.
"This should absolutely not be considered a beginning of an arms race," Kremlin spokesman Dmitry Peskov said Friday.
"These arms are not a threat to anyone who is not planning to attack our country," he added.
Peskov's comments come a day after Russian President Vladimir Putin boasted in his annual state of the nation address about his country's upgraded nuclear weapons arsenal.
Putin said that arsenal included "invincible" nuclear missiles that have unlimited range and which are capable of evading U.S. missile defense systems.
In response, White House Press Secretary Sarah Huckabee Sanders accused Russia of "developing destabilizing weapons systems for over a decade in direct violation of its treaty obligations."
NATO also criticized Russia, calling Putin's statements "unacceptable and counterproductive."
"We do not want a new Cold War or a new arms race," alliance spokesperson Oana Lungescu said in a statement Friday.
"All Allies support arms control agreements which build trust and confidence, for everyone's benefit," she said. "We continue to work for more military predictability and transparency."
Also Friday, Russia's RIA news agency reported Moscow has delayed planned talks with the U.S., set to focus on strategic stability.
The news agency quoted a Russian Foreign Ministry official as saying the postponement was in response to an earlier decision by Washington to cancel consultations on cybersecurity.
Tensions between Russia and the West have been growing following Russia's 2014 annexation of Ukraine's Crimea and its subsequent military buildup.
NATO members have since pledged to increase defense spending and bolster defenses along the alliance's eastern flank. But Moscow accuses the U.S. and NATO of aiming some of those defense systems, including anti-missile batteries, at Russia.
Both NATO and the U.S. reject that accusation.
Information from Reuters was used for part of this report.