The last remaining nuclear arms control agreement between the United States and Russia expired at midnight GMT on Thursday, removing the final formal limits on the two countries’ deployed strategic warheads and raising concerns about a renewed arms race.
New START, signed in 2010, and a series of earlier pacts had for decades capped the size of the two nations’ strategic nuclear forces. The treaty lapsed at midnight GMT (7 p.m. EST) after negotiators failed to reach an extension, the United Nations said. With the lapse, neither Washington nor Moscow is bound by treaty limits on deployed strategic nuclear warheads.
Russia’s Foreign Ministry said Moscow would continue to act responsibly but warned it would take “decisive” steps if it perceived threats to its security. The US government has not announced any move to continue observing the treaty’s limits after the deadline.
Former US President Donald Trump had said last year that a one‑year extension proposed by President Vladimir Putin “sounded like a good idea,” but no extension talks followed. Trump and some US lawmakers have insisted any new agreement should include China — a demand Beijing rejects and which Russia calls unnecessary.
President Putin spoke with Chinese President Xi Jinping following the treaty’s expiration, the Kremlin said, reiterating that Russia intends to act in a balanced, responsible way and remains open to further negotiations to preserve strategic stability.
Senator Marco Rubio said a decision on the treaty would be left to Trump and argued that China must be part of any future deal because of its growing nuclear arsenal. German Foreign Minister Johann Wadephul also called on China to show restraint in its weapons development and said Beijing should be involved in future arms control efforts.
United Nations Secretary‑General António Guterres described the treaty’s end as a “grave moment for international peace and security,” warning the risk of nuclear use is now the highest in decades. Pope Francis urged leaders to de‑escalate tensions and cautioned against abandoning the treaty without clear, effective follow‑up measures.
Reporting edited by Sean Sinico.