The New START treaty, signed in 2010, is the last remaining nuclear arms reduction agreement between the world's top two atomic powers and limits the number of nuclear warheads each side can deploy.

Talks on extending the agreement have broken down in recent years due to tensions over the Ukraine conflict, sparking fears that both sides will breach the limits once it expires.

"Fully abandoning the legacy of this agreement would be, from many perspectives, a mistaken and short-sighted step," Russian President Vladimir Putin said in a televised meeting.

"To avoid provoking a strategic arms race... Russia is prepared to continue adhering to the central quantitative limitations of the New START Treaty for one year after February 5, 2026," Putin added.

"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," he said.

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

- Nuclear sabre-rattling -

Anti-proliferation talks between the two sides, which together control more than 80 percent of the world's nuclear warheads, have deteriorated in recent years.

In 2019, the two countries withdrew from the landmark Intermediate-Range Nuclear Forces (INF) treaty.

Concluded in 1987 by then-US President Ronald Reagan and Soviet leader Mikhail Gorbachev, the agreement limited the use of medium-range missiles, both conventional and nuclear.

In 2023, Putin signed a law revoking Russia's ratification of the Comprehensive Nuclear Test Ban Treaty, although Moscow said it would stick to the moratorium on atomic testing.

Russia has also been accused of nuclear sabre-rattling since sending troops into Ukraine in February 2022.

Days after launching the assault, Putin put his nuclear forces on high alert.

The Russian leader last year signed a decree lowering the threshold for using nuclear weapons.

Tensions between the two sides have abated since US President Donald Trump came into office in January, but neither side has held substantive talks on the nuclear issue.

In August, Trump said he was moving two nuclear submarines in response to what he described as "highly provocative" comments by former Russian President Dmitry Medvedev.