On 6 August 1945, the United States dropped a bomb dubbed ‘Little Boy’, on the Japanese city of Hiroshima, as World War Two continued. The bombing resulted in immense devastation which killed and injured tens of thousands of people.

The Secretary-General insisted that the threat of the use of nuclear weapons is not just “confined to history books” but a “real and present danger” today – once again looming large “in the daily rhetoric of international relations.”

The lessons of Hiroshima

In a message delivered in the Japanese city by UN disarmament chief Izumi Nakamitsu, Mr. Guterres said the lessons of Hiroshima which encourage disarmament and peace have been “pushed aside” but he recognised the people of Hiroshima's efforts to ensure nuclear weapons are never used again.

He further insisted that the use of nuclear weapons is unacceptable and “a nuclear war cannot be won - and must never be fought.”

He said this is a lesson that shows we need disarmament now.

The message for the future

As the Hiroshima Peace Memorial ceremony continued, Mr. Guterres said that global mistrust and division have grown, but we must ensure not to “press our luck again.”

“Some are recklessly rattling the nuclear saber once more,” he said. “The world must stand together to condemn this unacceptable behaviour.”

Looking ahead to the Summit of the Future in New York next month, the Secretary-General said it is a “critical opportunity for governments to renew their commitment to multilateralism, sustainable development and peace, and adopt an actionable and forward-looking Pact for the Future.”

He said that conflict prevention, disarmament and a nuclear weapons-free world need to be at the heart of these efforts.

“We will never forget the lessons of 6 August 1945,” he said. “No more Hiroshimas. No more Nagasakis.”

Renewed determination

On Tuesday, UN disarmament chief, Ms. Nakamitsu echoed that message online.

In a statement on X, she also renewed her determination “to continue to work towards a world without nuclear weapons. For the security of all peoples.”