China on Tuesday urged the United States to “respond positively” to Russia’s offer to maintain nuclear warhead limits ahead of Thursday’s expected collapse of a major US-Russia agreement to control nuclear build-up.

Beijing also reiterated its refusal to join trilateral nuclear disarmament negotiations with Washington and Moscow, despite repeated calls for such talks by US President Donald Trump. China cited the disparity in nuclear stockpile sizes as the reason for its refusal.

Absent a last-minute move, the world will for the first time in decades be without a treaty limiting nuclear deployments by the United States and Russia, which together account for about 90 per cent of the world’s nuclear weapons.

The expiry of the New Strategic Arms Reduction Treaty (New Start) would mark a significant break in more than five decades of bilateral nuclear arms control.

Analysts warn that the end of the treaty could lead to a vicious circle and a three-way nuclear arms race involving the United States, Russia and China.

“China has taken note of the constructive suggestions previously made by Russia regarding the follow-up arrangements of the New Strategic Arms Reduction Treaty (New Start) and hopes that the United States will respond positively to truly safeguard global strategic stability,” Chinese foreign ministry spokesman Lin Jian said on Tuesday.

“China’s position on the trilateral nuclear arms control negotiations between China, the US and Russia is clear: the nuclear forces of China and the US are not on the same level at all, and it is neither fair nor reasonable to ask China to join the nuclear disarmament negotiations at this stage.”