The total number of nuclear warheads fell worldwide, but the amount of operational nuclear weapons started to rise.
Vladimir Putin said Russia will not withdraw from the treaty but will no longer allow NATO countries to inspect its nuclear arsenal, which is at the heart of the agreement.
The United States says Russia won't allow American inspectors to inspect its arsenal to ensure compliance with the post-Cold War agreement the two nations renewed for five years in 2021.
The U.S. and Russia agreed to renew New START for another five years in February 2021, just before it was set to expire. The treaty was extended without changes, but the prospect of new talks chilled with Russia's invasion of Ukraine.