The RT-2PM2, Topol-M, is one of the most recent intercontinental ballistic missiles to be deployed by Russia. Russian international military expo Army Expo 2022 at Patriot park in Kubinka, Moscow, Russia, on August 20, 2022.
CNN  — 

Russia is violating a key nuclear arms control agreement with the United States and continuing to refuse to allow inspections of its nuclear facilities, a State Department spokesperson said Tuesday.

“Russia is not complying with its obligation under the New START Treaty to facilitate inspection activities on its territory. Russia’s refusal to facilitate inspection activities prevents the United States from exercising important rights under the treaty and threatens the viability of U.S.-Russian nuclear arms control,” the spokesperson said in statement.

“Russia has also failed to comply with the New START Treaty obligation to convene a session of the Bilateral Consultative Commission in accordance with the treaty-mandated timeline,” the spokesperson added.

The US announcement is likely to increase tensions with relations between the two countries in the doldrums as Moscow continues its war on Ukraine. Russian President Vladimir Putin’s nuclear saber rattling during the war has alarmed the US and its allies.

In December, Putin warned of the “increasing” threat of nuclear war, and this month, Dmitry Medvedev, deputy head of Russia’s Security Council, threatened that Russia losing the war could “provoke the outbreak of a nuclear war.”

“Nuclear powers do not lose major conflicts on which their fate depends,” Medvedev wrote in a Telegram post. “This should be obvious to anyone. Even to a Western politician who has retained at least some trace of intelligence.”

And though a US intelligence assessment in November suggested that Russian military officials discussed under what circumstances Russia would use a tactical nuclear weapon in Ukraine, the US has not seen any evidence that Putin has decided to take the drastic step of using one, officials told CNN.

Under the New START treaty – the only agreement left regulating the world’s two largest nuclear arsenals – Washington and Moscow are permitted to conduct inspections of each other’s weapons sites, but due to the Covid-19 pandemic, inspections have been halted since 2020.

A session of the Bilateral Consultative Commission on the treaty was slated to meet in Egypt in late November but was abruptly called off. The US has blamed Russia for this postponement, with a State Department spokesperson saying the decision was made “unilaterally” by Russia.

The treaty puts limits on the number of deployed intercontinental-range nuclear weapons that both the US and Russia can have. It was last extended in early 2021 for five years, meaning the two sides will soon need to begin negotiating on another arms control agreement.

John Erath, senior policy director at the Center for Arms Control and Non-Proliferation, emphasized to CNN on Tuesday that Russia’s noncompliance “doesn’t mean that they are building vast numbers of nuclear weapons secretly.”

“That’s not the part that they’re being found not in compliance with,” he said. “It’s the verification provisions.”

But he added that Russia is likely using its noncompliance as leverage to attempt to end the war on their terms.

“They have fixed on New START as a piece of leverage they have,” Erath said. “They know that we would like to see it continue, and we would like to see it implemented because everybody feels better when there’s a functioning arms control agreement.”

Russia, he continued, is “using their noncompliance as a way to gain a little bit more leverage so that we will say, ‘Oh, this war is threatening arms control, that’s important to us. Hey Ukrainian friends, don’t you think you’ve done enough? How about stopping?’”

Lawmakers responded by warning that any future arms control arms control agreement with Russia could be in jeopardy if the situation is not salvaged.

“We have long supported strategic arms control with Russia, voting for New START in 2010 and advocating for the Treaty’s extension during both the Trump and Biden administrations. But to be very clear, compliance with New START treaty obligations will be critical to Senate consideration of any future strategic arms control treaty with Moscow,” wrote Democratic senators Bob Menendez, Jack Reed, Mark Warner in a joint statement.

The State Department says Russia can return to full compliance, if they “allow inspection activities on its territory, just as it did for years under the New START Treaty” and also scheduling a session of the commission.

“Russia has a clear path for returning to full compliance. All Russia needs to do is allow inspection activities on its territory, just as it did for years under the New START Treaty, and meet in a session of the Bilateral Consultative Commission,” the spokesperson said. “There is nothing preventing Russian inspectors from traveling to the United States and conducting inspections.”

According to the Center for Arms Control and Non-Proliferation, Russia has roughly 5,977 nuclear warheads, 1,588 of which are deployed. The US has 5,550 nuclear warheads, according to the Center, including 3,800 active warheads.

Administration officials have said that the willingness to discuss the arms control agreement, even as Russia carries out its war in Ukraine, demonstrates the US commitment to diplomacy and mitigating the risk of nuclear catastrophe.

But Russia has indicated in recent days that the US support for Ukraine is preventing the treaty from being renewed.

On Monday, Russia’s Deputy Foreign Minister Sergei Ryabkov said the last remaining element of the bilateral nuclear arms control treaty with the United States could expire in three years without a replacement.

Asked if Moscow could envisage there being no nuclear arms control agreement between the two nations when the extension of the 2011 New START Treaty comes to an end after 2026, Ryabkov told the Russian state news agency RIA Novosti on Monday: “This is a very possible scenario.”

CNN’s Jonny Hallam contributed reporting.