The Russian foreign ministry's head of nuclear non-proliferation, Vladimir Yermakov, said that if the US doesn't back off, the Kremlin could do away with the Treaty Between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms, better known as the New START Treaty, which limits the number of deployed strategic nuclear warheads both nations can have at any given time.
According to Reuters, Yermakov told the TASS news agency that, "if the United States continues to follow its current course of confrontation with Russia, with the stakes constantly escalating on the verge of sliding into direct armed conflict, then the fate of START may be a foregone conclusion."
"The most acute threat today is associated ... with the danger of nuclear escalation as a result of a direct military confrontation between nuclear powers," Yermakov warned, "and these risks, to the deepest regret, are steadily growing."
In the months since Putin ordered the illegal invasion of Ukraine, Russia has repeatedly blamed the US, and the West in general, for escalating the conflict. In February, the Kremlin announced that Russia was suspending its participation in the New START Treaty, and that "the Ministry of Defense must ensure that Russia is ready to test its nuclear weapons."
US Secretary of State Antony Blinken called Putin's decision "deeply unfortunate and irresponsible," sentiments shared by numerous other officials within the US government and NATO. In response, the US told Russia that it would no longer provide certain data relating to its nuclear capabilities.
The US has been, by far, the largest supporter of Ukraine in its fight to stave off Russia's invasion. Over $40 billion in military aid has been sent from Washington to the war-torn nation.