NATO Secretary General Jens Stoltenberg has asked Russia to reconsider its decision to suspend participation in the treaty with the United States that limits the strategic nuclear arsenals of both sides.
In his February 21 address to the nation, Russian President Vladimir Putin said he was "obliged to announce that Russia is suspending participation in the Strategic Arms Treaty."
He said that Russia is not withdrawing from the agreement, but is only suspending its participation.
The so-called New START, the only nuclear weapons treaty between the United States and Russia, has been extended for five years through 2021.
Originally signed in 2010, this treaty limits the parties' possession of long-range nuclear warheads to 1,550, a smaller number than was in the original agreement.
Stoltenberg said that Russia is preparing for the escalation of the war, not for peace.
He said NATO is planning to hold a meeting with arms procurement experts to make sure Ukraine gets the weapons it needs.
Top European Union diplomats warned on Monday that ways must be found to quickly deliver thousands of artillery shells to Ukraine or the EU will have to face the possibility of losing the war against Russia.
Last week, Stoltenberg said the waiting time for the supply of "large-caliber ammunition has increased from 12 to 28 months."
Ukrainian President Volodymyr Zelensky has called on his Western allies to speed up their military support, warning that delays will benefit Russia as the first anniversary of the start of the war in Ukraine approaches on February 24.
NATO believes that Russia has launched a new offensive in recent weeks, increasing the intensity of attacks in eastern Ukraine, while also increasing forces in the south. Officials have said Ukraine is likely to launch its counteroffensive in the spring.