The elimination of nuclear weapons must begin with an end to the "Cold War mentality", a Chinese envoy told a high-level conference of the United Nations General Assembly.

"With such a mentality, the world cannot achieve real nuclear disarmament and will not enjoy real peace and tranquility," China's deputy permanent representative to the UN, Geng Shuang, said at the plenary meeting on Tuesday that commemorated the International Day for the Total Elimination of Nuclear Weapons.

The envoy noted that 2021 marks the 30th year since the end of the Cold War. However, three decades on, nuclear weapons still exist, the threat of nuclear warfare has yet to be eliminated, and the building of a world free of nuclear weapons is still "an arduous task".

All of this is "ultimately attributable to the lingering shadow of the Cold War in the minds of some",Geng said.

"In recent years, some individual countries have been sticking to the Cold War mentality, seeking absolute military superiority, pursuing an offensive nuclear policy, shunning responsibility for nuclear disarmament, obsessed with forming closed and exclusive small circles and bent on provoking conflicts and confrontation," Geng said.

He noted that a couple of countries had "blatantly" announced cooperation on nuclear-powered submarines recently, which will result in "serious nuclear proliferation risks", he said.

"Such practice heightens regional tensions, stimulates the arms race, undermines international efforts in nuclear nonproliferation, and runs counter to the goal of the total elimination of nuclear weapons as well as the aspiration of regional countries for peace and development," the envoy said.

In a trilateral security partnership announced last month, the United States and the United Kingdom agreed to support Australia, a nonnuclear-weapon state, in developing nuclear-powered submarines. The pact became known as AUKUS.

Geng recalled that "a country" stated in the General Assembly Hall a week ago that it does not seek a cold war and has no intention of creating division, in reference to US President Joe Biden's remarks at the UN General Debate on Sept 21.

"We hope that this public pronouncement made before the whole world will be shown in action," he said. "We hope that the relevant country will discard the outdated zero-sum mentality of the Cold War era and narrow-minded geopolitical concepts and make concrete efforts to maintain global strategic balance and stability and uphold regional peace and security."

Since the first day that it came into possession of nuclear weapons, China has been advocating the prohibition and destruction of nuclear weapons, Geng said.

"China has declared that it will not be the first to use nuclear weapons at any time and under any circumstance, and unconditionally committed itself not to use or threaten to use nuclear weapons against nonnuclear-weapon states or nuclear-weapon-free zones," the envoy said.

Geng noted that this year marks the 50th anniversary of the restoration of China's lawful seat in the UN. Over the past 50 years, China has participated in UN disarmament pursuits "in an in-depth and comprehensive manner".