Russia and the US have agreed to extend the New START nuclear arms reduction treaty by five years, the Kremlin said on Tuesday.
Moscow said the two countries have exchanged diplomatic notes agreeing to extend the accord, which was due to expire in February.
The announcement on Tuesday evening followed a first phone call between Russian President Vladimir Putin and his US counterpart Joe Biden.
The US has not yet confirmed the agreement but both sides had previously declared their willingness to extend the last remaining nuclear arms agreement between the two countries.
The New START (Strategic Arms Reduction Treaty) agreement went into effect in 2011 and establishes a deal between the US and Russia setting controls on weapons stockpiles and allowing inspections.
The treaty limits both Russian and US intercontinental ballistic missile stockpiles and submarine missile launchers able to deploy nuclear weapons, among other restrictions.
Concerns over Moscow's actions
Earlier on Tuesday Jenn Psaki, the White House press secretary, confirmed Biden and Putin had held an initial call in which Biden had reiterated that the US wanted to extend the treaty.
Biden also expressed a host of concerns over Moscow's actions, including a massive cyberattack on US government agencies, which the US has blamed on Russia.
Biden also planned to reaffirm US support for Ukraine in the face of Russia's "ongoing aggression," reports of Russia placing bounties on US soldiers in Afghanistan, Russian interference in the 2020 presidential election and the poisoning of Russian opposition leader Alexei Navalny.
The call signalled a marked shift in US rhetoric on Russia, after years of former President Donald Trump downplaying Russian responsibility and often refusing to criticize or confront Putin.
