US President Joe Biden has called Russia's decision to suspend the New Start nuclear arms treaty a big mistake.
President Vladimir Putin announced the move on Tuesday in his annual address to the nation.
The deal, signed in 2010, limits the number of US and Russian nuclear warheads and gives each the power to inspect the other's weapons.
Mr Biden's comments came as he met a key group of Nato allies in Poland.
The group of eastern European states, known as the Bucharest Nine, reiterated their condemnation of Russia's invasion of Ukraine nearly a year since its start.
Putin's decision to suspend involvement in the nuclear treaty was officially pushed through by both houses of Russia's parliament on Wednesday. baccarat168
But Russia's foreign ministry later said Moscow would continue to comply with the New Start treaty's restrictions in a "responsible approach".
A senior military official told Russia's lower house that the country would continue to observe agreed restrictions on nuclear delivery systems - meaning missiles and strategic bomber planes.