The New START treaty, signed in 2010, limits the number of nuclear warheads each side can deploy and is the last major arms proliferation agreement between the two nuclear powers.

It is set to expire on February 5, 2026, and neither side has agreed an extension.

"Russia is prepared to continue adhering to the central quantitative limitations of the New START Treaty for one year after February 5, 2026," Russian President Vladimir Putin said in a televised meeting.

He said the measure was needed to prevent "a strategic arms race" with Washington.

"We believe that this measure will only be viable if the United States acts in a similar manner and does not take steps that undermine or disrupt the existing balance of deterrence potentials," Putin added.

Russia froze its participation in New START in 2023 but has continued to voluntarily follow the numerical limits in the treaty.

The agreement restricts both sides to a maximum of 1,550 deployed strategic nuclear warheads each, a reduction of nearly 30 percent from the previous limit set in 2002.