Five world powers have agreed to work together to stop the further spread of nuclear arms and to avoid nuclear conflict, according to a joint statement.
"We believe strongly that the further spread of such weapons must be prevented," said the five permanent U.N. Security Council members China, France, Russia, Britain and the United States, collectively known as the P5.
"We affirm that a nuclear war cannot be won and must never be fought," the countries added.
The statement Monday from the P5 countries comes as tensions escalate between Western nations and Moscow over Russia's troop buildup at its border with Ukraine. Relations between the U.S. and China are also strained over disagreements such as alleged human rights abuses by Beijing, disputes over the South China Sea and Chinese military flights near Taiwan.
Despite the tensions, the five nuclear powers said they saw "the avoidance of war between nuclear-weapon states and the reduction of strategic risks" as their "foremost responsibilities."
The statement came after a scheduled review on Tuesday of the Treaty on the Non-Proliferation of Nuclear Weapons was postponed to later in the year because of the coronavirus pandemic.
The five world powers said they were committed to a key article in the treaty, which calls for countries to work toward full disarmament of nuclear weapons in the future.
The Russian Foreign Ministry welcomed the declaration.
"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," it said in a statement.
Monday's declaration also comes as diplomats resume talks aimed at reviving Iran's 2015 nuclear deal with world powers.
The administration of former U.S. President Donald Trump quit the nuclear deal in 2018, saying it was not tough enough on Iran, and reimposed U.S. sanctions. Iran retaliated a year later by publicly exceeding nuclear activity limits agreed on as part of the 2015 deal. President Joe Biden has said he wants to honor the deal again if Iran does the same.
The U.S. has repeatedly warned that time is running out for Iran to agree to a new deal.
Some information in this report came from Reuters and Agence-France Presse.
