The last nuclear weapons control treaty between the US and Russia is due to expire, raising fears of a new arms race.

The Strategic Arms Reduction Treaty, known as New START and signed in 2010, was designed to help prevent catastrophic nuclear war.

The treaty capped the number of deployed strategic nuclear warheads for each party to 1,550. It also established transparency measures, including data transfer and notifications.

Its expiry effectively marks an end to the arms control cooperation that helped bring an end to the Cold War.

On Wednesday, Pope Leo urged both nations to renew the treaty, emphasizing the need to do everything possible to avert an arms race.

Admiral Sir Tony Radakin cautioned that the frameworks that have historically safeguarded global security are at risk, describing the collapse of key arms control initiatives as one of the most dangerous aspects of current global security.

With both the US and Russia modernizing their nuclear arsenals, experts warn that a new arms race could be imminent, underscoring the need for renewed arms control discussions.