Russian President Vladimir Putin has signed a bill formally suspending the last remaining nuclear arms treaty with the United States, amid soaring tensions with Washington over Moscow’s action in Ukraine.

He had declared a week ago in his state-of-the-nation address that Moscow was suspending its participation in the 2010 New Start treaty.

He claimed Russia could not accept US inspections of its nuclear sites under the pact at a time when Washington and its NATO allies have openly declared Russia’s defeat in Ukraine as their goal.

Both houses of parliament quickly ratified Putin’s bill on the pact’s suspension last week, and on Tuesday he signed it into law, effective immediately.

The document says it is up to the president to decide whether Moscow could return to the pact.

President Putin has emphasised that Moscow is not withdrawing from the pact altogether, and the Russian Foreign Ministry said the country would respect caps on nuclear weapons set under the treaty and keep notifying the US about test launches of ballistic missiles.

On Monday, a senior US arms control official criticised Russia for suspending its participation in the treaty, but noted that Washington will try to work with Moscow to continue its implementation.

“Russia is once again showing the world that it is not a responsible nuclear power,” Bonnie Jenkins, the US undersecretary of state for arms control, said at a session of the Conference on Disarmament, a United Nations-affiliated international forum.

She told reporters the US has not fully assessed the consequences of Russia’s move, but said: “We’re not seeing any evidence that Russia is in non-compliance.

“We remain ready to work assertively with Russia to fully implement the New Start treaty.”

The New Start, signed by then-presidents Barack Obama and Dmitry Medvedev in 2010, limits each country to no more than 1550 deployed nuclear warheads and 700 deployed missiles and bombers.

The agreement envisages sweeping on-site inspections to verify compliance.

The inspections have been dormant since 2020 because of the COVID-19 pandemic. Discussions on resuming them were supposed to have taken place last November, but Russia abruptly called them off.

– AAP