End of US-Russia nuclear pact as New START expires, UN chief warns

The New START treaty between the United States and Russia has expired, removing binding limits on their strategic nuclear arsenals; UN Secretary‑General António Guterres described the timing as "grave" and urged both powers to return to negotiations for a successor framework.

The New START treaty between the United States and Russia expired on Thursday, formally lifting binding limits on their strategic nuclear arsenals. UN Secretary‑General António Guterres called the timing "grave" for international peace and security and urged Washington and Moscow to return to the negotiating table to agree a successor framework. The treaty, signed in 2010, had capped deployed strategic warheads and included verification measures. Its expiry comes ahead of a scheduled review of the 1970 nuclear non‑proliferation treaty. Key facts: - New START formally expired, removing treaty limits and related verification obligations between the United States and Russia. - António Guterres described the moment as "grave" and publicly urged both countries to negotiate a successor agreement without delay. - The article reports that the United States and Russia control more than 80% of the world’s nuclear warheads. - A review of the 1970 nuclear non‑proliferation treaty is scheduled later this year, and observers have linked the treaty’s expiry to possible implications for non‑proliferation efforts. Summary: The expiry ends a key bilateral arms control agreement and has prompted international concern about rising strategic risk. UN officials and other commentators have urged immediate talks; the next noted international milestone is the upcoming NPT review this year, while the timing and format of successor negotiations remain undetermined at this time.