United Nations secretary-general Antonio Guterres has urged countries with nuclear weapons to stick to their no-first-use commitment on their atomic arsenals, warning that the arms race has returned amid growing international tension.
"This is the moment... to ask the nuclear-armed countries to commit to the principle of non-first-use and to commit to not use and not threaten the non-nuclear countries," he said at a news conference in Tokyo, two days after he visited Hiroshima to commemorate victims of the atomic bombing on August 6 1945.
"I think that nobody, nobody can accept the idea that a new nuclear war would happen. This will be the destruction of the planet," Mr Guterres said.
"What is clear is if nobody uses for the first time then there will be no nuclear war."
Fears of a third atomic bombing have been on the rise amid Russia's threats of a nuclear attack since its war on Ukraine began in February.
On Thursday, Moscow shelled the Ukrainian city of Zaporizhzhia, which holds Europe's largest nuclear plant. Asked about the attack, Mr Guterres said: "Any attack to a nuclear plant is a suicidal thing."
He said he supports the International Atomic Energy Agency in their effort to stabilise the plant and have access to the facility to exercise its mandate.
Mr Guterres said that after decades of nuclear disarmament efforts, the world is now "moving backwards", noting that the world already has 13,000 nuclear bombs and huge investment going into modernisation of atomic arsenals. "So this is the time to say: Stop it."
He said the billions of dollars being used in the arms race should be spent on other pressing issues.
"The billions that are being used in this arms race need to be used to fighting climate change, fighting poverty, addressing the needs of the international community," he said.
He added he will be also going to Mongolia and South Korea to discuss ways to address North Korea's nuclear development.
Asked about China's military exercises surrounding Taiwan, Mr Guterres said the UN abides by the general assembly resolution supporting the "One China" policy, which acknowledges Beijing's view that it has sovereignty over Taiwan, but considers Taiwan's status as unsettled.
"We all want that resolution to correspond to a peaceful environment," he said, calling for "common sense and then restraint, allowing for de-escalation".
Earlier on Monday, Mr Guterres met Japanese foreign minister Yoshimasa Hayashi and shared "serious concern about the tense situation in the region and concurred on the importance of de-escalating the tension", the ministry said.