MOSCOW — President Vladimir Putin boasted about the strength of Russia's nuclear arsenal Friday but told reporters he would not be drawn into an arms race with U.S. at any cost.

Putin's comment came after president-elect Donald Trump stunned experts by suggesting the U.S. should expand its nuclear capabilities.

Putin dismissed Trump's rhetoric as nothing new during an annual press conference, and said Russia had nuclear warheads that could penetrate U.S. defense systems.

"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."

On Thursday, Trump said "the United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes.”

He followed that statement up Friday morning by telling MSNBC’s Mika Brzezinski in a telephone call: “Let it be an arms race. We will outmatch them at every pass and outlast them all.”

No president has called for an increase in the country’s estimated 4,500 nuclear arms in decades.

According to the Federation of American Scientists, the global stockpile of nuclear weapons has declined significantly since the end of the Cold War.

It estimates that there were currently 15,350 in nukes in existence in early 2016, down from a peak of approximately 70,300 in 1986.

It was unclear whether Trump was aware of Putin's comments on overcoming U.S. missile defenses when speaking to MSNBC.

During the press conference, Putin also said it "was not surprising that [Trump] talks about nuclear weapons, he talked about the necessity to strengthen the nuclear and defense sector in the U.S. during his campaign."

Putin added that the modernization of Russian nuclear forces was in line with existing arms control agreements, including the New Start Treaty with the U.S.

The New Start treaty, which was signed by President Barack Obama and former Russian President Dmitry Medvedev in 2011, limited the number of strategic warheads both Russia and the U.S. could possess.

The pact also reestablished a monitoring system that ended in December 2009 with the expiration of an earlier arms deal.

Obama has proposed a $500 billion plan to modernize the aging U.S. nuclear triad, which consists of bomber, intercontinental missiles and submarines delivery methods for nukes.

James Mattis, the retired Marine general who is Trump's choice for defense chief, has questioned the purpose of the triad system.

"You should ask, 'Is it time to reduce the triad to a diad, removing the land-based missiles?'" he told the Senate Armed Services Committee in January 2015, as the AP reported earlier this month.

Alleged Hacking

Putin also addressed the issue of alleged Russian hacking Friday, stating it was not important who hacked the Democratic Party prior to the presidential election. He added that the hacks revealed that public opinion in America was being manipulated behind the candidacy of Hillary Clinton and against Bernie Sanders during the primaries.

Senior U.S. officials have told NBC News they believed "with a high level of confidence" that Putin was personally involved in a covert Russian campaign to interfere in the U.S. presidential election.

Russia has consistently denied accusations Moscow was involved in cyberattacks against the U.S. and on Friday Putin echoed language used by Trump by saying it was impossible to know who was behind the election hacks.

“Maybe they were in some other country and not Russia. Maybe someone did [it] lying on the sofa or bed,” he said.

Trump has also repeatedly rejected claims that Russian hacking influenced the outcome of the election in his favor.

He told Fox news on December 11 “once they hack, if you don't catch them in the act you're not going to catch them. They have no idea if it's Russia or China or somebody. It could be somebody sitting in a bed some place.”