Japan's Prime Minister Fumio Kishida and United States Ambassador to Japan Rahm Emanuel visited the city of Hiroshima, where the first atomic bomb fell 75 years ago.

Japan, the only country attacked by atomic weapons, has regularly spoken out against nuclear armaments. Kishida, who represents Hiroshima in parliament, visited the city's peace memorial and museum on Saturday with envoy Rahm Emanuel.

The two politicians offered flowers to the cenotaph for the victims of the U.S. atomic bombing in 1945.

"When the possible use of nuclear weapons by Russia is increasingly real, I believe Ambassador Emanuel's visit to Hiroshima and his experience of seeing the nuclear reality will become a strong message to the international society," Kishida told public broadcaster NHK.

Ambassador Emanuel has issued a statement after his visit. "During World War II, our countries were adversaries on the battlefield. Through hard work and cooperation we became allies and the best of friends, standing side by side in defense of freedom and common ideals as we confront oppression," he said. (via U.S. Mission Japan)

"Today, we live in unprecedented times as Russia threatens the use of nuclear weapons, something that was once unthinkable, even unspeakable. The history of Hiroshima teaches us that it is unconscionable for any nation to make such a threat," he added. (via U.S. Mission Japan)

Kremlin spokesperson Dmitry Peskov said on Tuesday that Russia would use nuclear weapons only to counter "an existential threat for our country."

Leaders of the G7 industrial powers on Thursday warned Russia not to use biological, chemical or nuclear weapons in its war with Ukraine.