The rare joint statement comes amid negotiations over reviving the Iran nuclear deal and escalating tensions between the United States, Russia and China.
Five global nuclear powers have pledged to prevent atomic weapons spreading and to avoid nuclear conflict, in a rare joint statement ahead of a review of a key nuclear treaty later this year.
"We believe strongly that the further spread of such weapons must be prevented," said UN Security Council members China, France, Russia, the United Kingdom and the United States on Monday.
"A nuclear war cannot be won and must never be fought," the members said, putting aside current differences that have caused major tensions between both China and Russia and their Western partners.
The powers added, "We each intend to maintain and further strengthen our national measures to prevent unauthorised or unintended use of nuclear weapons."
Increasing 'mutual trust'
Russia welcomed the declaration by the atomic powers and expressed hope it would reduce global tensions.
"We hope that, in the current difficult conditions of international security, the approval of such a political statement will help reduce the level of international tensions," the Russian Foreign Ministry said in a statement.
Kremlin spokesman Dmitry Peskov told the RIA Novosti news agency that Moscow still considered a summit between the world's nuclear powers to be "necessary".
Chinese Vice Foreign Minister Ma Zhaoxu stated to the official Xinhua news agency that the joint agreement "will help increase mutual trust and replace competition among major powers with coordination and cooperation".
Ma described the agreement as "positive and weighty", adding it would help create a "balanced relationship between major powers".
Amid rising tensions
The statement was issued after the latest review of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) had been postponed from its scheduled date of January 4 to later in the year due to the Covid-19 pandemic.
It comes as tensions between Russia and the United States have reached heights rarely seen since the Cold War over a troop build-up by Moscow close to the Ukrainian border.
Meanwhile, the rise of China under President Xi Jinping has also raised concerns that tensions with Washington could lead to conflict, notably over the island of Taiwan.
In addition, the statement comes as the world powers seek to reach agreement with Iran on reviving the 2015 deal over its controversial nuclear drive.