(Bloomberg) -- Russia is breaching the terms of the New START nuclear-arms reduction treaty by refusing to allow inspectors on its territory and stonewalling US efforts to discuss the issue, the State Department said Tuesday.

The department said in a statement that the Russian refusal “prevents the United States from exercising important rights under the treaty and threatens the viability of US-Russian nuclear arms control.”

Russia dismissed the allegations, saying it remains committed to the goals of the treaty as it sought to shift the blame to the US. 

“We have repeatedly pointed out to the Administration that the situation with New START is a direct result of the hybrid war unleashed by the West against our country,” Anatoly Antonov, Russia’s ambassador to the US, wrote in Facebook, referring to the response by Washington and its allies to Moscow’s invasion of Ukraine. “In the current circumstances we consider it unjustified, untimely and inappropriate to invite the US military to our strategic facilities.”

The US and Russia extended the New START treaty for five years in 2021, giving the former Cold War rivals time for new talks on strategic security. But inspections were shut down because of the Covid-19 pandemic, and the US says Russia rebuffed efforts to restart those visits last August, in part because of tensions resulting from the Russian invasion of Ukraine. 

A US bid to restart consultations in Cairo in recent months also failed. 

The treaty between the US and Russia seeks to limit the deployment of intercontinental-range nuclear weapons on both sides by allowing frequent checks of each country’s programs. Under the agreement, both countries are allowed as many as 700 deployed intercontinental ballistic missiles and 1,550 nuclear warheads on those missiles.  

If New START is terminated or allowed to expire, the nuclear arsenals of the world’s two largest nuclear powers would have no treaty-based limitation for the first time since the 1970s. Neither side would have any means to inspect the other’s stockpiles. 

The warning from Washington comes as the US and its allies have increasingly sent more sophisticated weapons to Ukraine in its effort to push Russian forces out of its territory, even as they’ve been cautious not to be drawn into a war with a nuclear power.

US and NATO officials have castigated Russian President Vladimir Putin over “nuclear saber-rattling” given his threatening rhetoric since Russia’s invasion of Ukraine. Russian officials have been less vocal with nuclear threats in recent months, particularly after Chinese President Xi Jinping said in the fall that he opposed the use of nuclear force in Europe.

(Updates with Russian response from third paragraph)

©2023 Bloomberg L.P.