AN emotional John Kerry said Hiroshima’s horrible history should teach humanity to avoid conflict and strive to eradicate nuclear weapons as he became the first US secretary of state to tread upon the ground of the world’s first atomic bombing.

Kerry’s visit to the Japanese city included him touring its peace museum with other foreign ministers of the Group of Seven industrialised nations and laying a wreath at the adjoining park’s stone-arched monument, with the exposed steel beams of Hiroshima’s iconic A-Bomb Dome in the distance.

The US attack on Hiroshima in the final days of World War II killed 140,000 people and scarred a generation of Japanese, while thrusting the world into the dangerous atomic age. But Kerry hoped his trip would underscore how Washington and Tokyo have forged a deep alliance over the last 71 years and how everyone must ensure that nuclear arms are never used again.

“While we will revisit the past and honour those who perished, this trip is not about the past,” he told Japanese Foreign Minister Fumio Kishida, a Hiroshima native. “It’s about the present and the future particularly, and the strength of the relationship that we have built, the friendship that we share, the strength of our alliance and the strong reminder of the imperative we all have to work for peace for peoples everywhere.” Kerry’s appearance, just footsteps away from ground zero, completed an evolution for the United States, whose leaders avoided the city for many years because of political sensitivities.

No serving US president has visited the site, and it took 65 years for a US ambassador to attend Hiroshima’s annual memorial service. Many Americans believe the dropping of atomic bombs here on August 6, 1945, and on the Japanese city of Nagasaki three days later were justified and hastened the end of the war.

Hours afterwards, the top American diplomat still seemed to be absorbing all that he saw.

“It is a stunning display, it is a gut-wrenching display,” he told reporters of the museum tour, recounting exhibits that showed the bomb, the explosion, the “incredible inferno” and mushroom cloud that enveloped Hiroshima on August 6, 1945. “It tugs at all of your sensibilities as a human being. It reminds everybody of the extraordinary complexity of choices of war and what war does to people, to communities, countries, the world.”

Kerry urged all world leaders to visit, saying: “I don’t see how anyone could forget the images, the evidence, the recreations of what happened.” Japanese survivors’ groups have campaigned for decades to bring leaders from the U.S. and other nuclear powers to see Hiroshima’s scars as part of a grassroots movement to abolish nuclear weapons. As Kerry expressed interest, neither Japanese government officials nor survivor groups pressed for the US to apologise. And Kerry didn’t say sorry.

“I don’t think it is something absolutely necessary when we think of the future of the world and peace for our next generation,” Masahiro Arimai, a 71-year-old Hiroshima restaurant owner, said of an apology.

Wading into US politics, both Kerry and his Japanese counterpart rejected Republican presidential candidate Donald Trump’s recent suggestion that Japan consider developing its own nuclear weapons to defend itself against nuclear-armed North Korea. Kishida said, “For us to attain nuclear weapons is completely inconceivable.” Kerry called such notions “absurd on their face,” contradicting the efforts of every Democratic and Republican president since World War II to prevent wider nuclear proliferation.