Washington DC: The United Nations has warned of a serious threat to global peace and security as the US-Russia New START treaty, the last remaining agreement limiting the world’s two largest nuclear arsenals, expires on Friday.
UN Secretary-General António Guterres said the expiration marks an unprecedented moment, leaving the world without any binding constraints on the nuclear weapons held by the United States and Russia. He described the situation as a grave setback to decades of arms control efforts and cautioned that the risk of nuclear weapon use is now at its highest level in decades.
Guterres urged both Washington and Moscow to immediately resume negotiations and work toward a successor framework that restores verifiable limits, reduces strategic risks and reinforces global security. He said the treaty’s lapse represents the dismantling of hard-won achievements in nuclear arms reduction at a time when geopolitical tensions are already dangerously high.
The UN chief noted that the United States and Russia together possess the vast majority of the world’s nuclear weapons, making bilateral arms control between the two nations critical for international stability. He said the New START treaty had significantly improved global security, particularly for the citizens of both countries.
Throughout the Cold War and the years that followed, nuclear arms control agreements between the two powers played a crucial role in preventing catastrophic miscalculations. Guterres said these measures created strategic stability and enabled the elimination of thousands of nuclear warheads from national stockpiles.
The New START treaty was signed in 2010 by then US President Barack Obama and former Russian President Dmitry Medvedev. It imposed strict limits on strategic nuclear weapons designed to target key political, military and industrial centres in the event of a nuclear conflict. Under the agreement, each side was limited to 1,550 deployed strategic warheads and no more than 700 deployed missiles and bombers, with a total cap of 800 launchers.
The treaty also established a regime of short-notice, on-site inspections to verify compliance. However, Russia suspended its participation in 2023, citing US support for Ukraine in the ongoing conflict. Inspections were halted, forcing both sides to rely solely on intelligence assessments to monitor each other’s nuclear capabilities.
With the treaty’s expiration and no successor agreement in place, the end of more than five decades of nuclear arms limitations looms. Experts warn that without legally binding constraints, either country could expand its missile forces and deploy hundreds of additional strategic warheads, further destabilising the global security environment.
