US officials say Russia has postponed nuclear weapons talks

US officials said Russia had postponed crucial nuclear weapons talks that were due to begin on Tuesday, marking a setback for the last remaining arms treaty between the powers and providing further evidence of fraying diplomatic ties since Moscow’s invasion of Ukraine.

On Monday, John Kirby, a spokesman for the US National Security Council, said: “We haven’t received a real solid answer from the Russians as to why they postponed this. We’d like to see it get back on the schedule as soon as possible.”

A Russian foreign ministry official told the Tass news agency that the talks would be rescheduled, but offered no other details. US officials said they were working to ascertain why Moscow postponed the discussions.

The meeting would have been the first of its kind since the beginning of the Covid-19 pandemic. Since its implementation in 2011, the New Start Treaty has limited Moscow and Washington’s strategic nuclear weapons arsenals and allowed the parties to conduct on-site inspections to verify that those limits are being adhered to. It is set to expire in 2026.

Over the summer, Russian officials had said they would not allow the inspections to resume, citing US sanctions relating to Russia’s war in Ukraine, which Moscow said would make travelling for the inspections difficult.

However, US officials had hoped this week’s meeting would allow them to discuss restarting the inspections.

A state department official said Russia made the decision to scrap the talks “unilaterally”, and added that Washington hopes to return soon to the technical talks on implementing the treaty.

“The United States is ready to reschedule at the earliest possible date as resuming inspections is a priority for sustaining the treaty as an instrument of stability,” the official said.

US and European officials have made considerable efforts to avoid nuclear escalation as Russia’s full-scale invasion of Ukraine rumbles on. Washington is particularly concerned that Russian president Vladimir Putin may try to use a tactical or battlefield nuclear weapon — which are not included in the treaty — in Ukraine as he continues to face military setbacks.

CIA director Bill Burns met with his Russian counterpart in Turkey earlier this month to warn of the consequences of using nuclear weapons, while senior American officials have stepped up conversations with their counterparts in recent months to do the same.