US Ambassador John Roos at the Peace Memorial Park in Hiroshima, marking the 65th anniversary of the bombing. Photograph: Jiji Press/AFP/Getty Images
The US ambassador to Japan, John Roos, today became the first US representative to attend an annual ceremony to honour the victims of the bombing of Hiroshima.
Roos's presence at an event to mark 65 years since a US bomb left Hiroshima in ruins has raised hopes that president Barack Obama will visit the city when he attends a meeting of Apec leaders in Japan in November.
The mayor of Hiroshima, Tadatoshi Akiba, welcomed Washington's decision to send Roos, after it had previously turned down invitations to mark the moment a B-29 bomber dropped an atomic bomb on the city on the morning of 6 August 1945.
"We need to communicate to every corner of the globe the intense yearning of the survivors for the abolition of nuclear weapons," Akiba said. "I offer my prayers to those who died. We will not make you wait for much longer [for nuclear disarmament]."
An estimated 140,000 people were killed instantly or died from the effects of radiation in the months that followed. A further 80,000 people died after the US dropped an atomic bomb on Nagasaki three days later.
The US has since justified the bombings as an alternative to a potentially prolonged and costly land invasion, saying the devastation wrought on the cities forced Japan's surrender days later, on 15 August.
Some of the 55,000 people attending today's ceremony made symbolic offerings of water to the victims, as many had complained of thirst as they lay dying, while schoolchildren read out messages of peace. A single bell tolled as the city's people fell silent at 8:15am, the exact time "Little Boy" detonated.
Envoys from France and Britain – both nuclear powers – and the UN secretary general, Ban Ki-moon, also attended for the first time.
Roos did not speak at the ceremony, but said in a statement that his attendance was proof of the Obama administration's commitment to disarmament.
"For the sake of future generations, we must continue to work together to realise a world without nuclear weapons," he said.
Conservatives in the US have criticised the decision to send Roos, saying it would be misinterpreted as an act of contrition. The son of a member of the Enola Gay crew said the ambassador's visit to Hiroshima amounted to an "unspoken apology".
Gene Tibbets, whose deceased father, Brig Gen Paul Tibbets, piloted the bomber, told Fox News: "It's making the Japanese look like they're the poor people, like they didn't do anything. They hit Pearl Harbor, they struck us. We didn't slaughter the Japanese. We stopped the war."
The prospect of a first visit to Hiroshima by a sitting US president has also divided opinion in Japan.
"I'm not sure if I would welcome president Obama here," Katsuki Fujii, a college student, told Associated Press. "I don't think we have the same idea of what peace is. He seems to think some wars are good and some are bad. I think they are all bad."
Japan's long campaign to persuade the world's nuclear powers to disarm sits uneasily with its postwar dependence on the US nuclear umbrella.
The prime minister, Naoto Kan, said Japan must continue to look to its ally for security in "uncertain times" – a clear reference to the perceived threat from a nuclear North Korea.
"I think that nuclear deterrence continues to be necessary for our nation at a time when there are unclear and uncertain factors," Kan said. "We share strong hopes for nuclear disarmament, but the reality is that nuclear arms and other weapons of mass destruction are spreading."
Hiroshima aftermath
The 65th anniversary of the  has been remembered in a ceremony Thursday in , Japan.

The atomic bomb, code-named "", was dropped on Hiroshima at precisely 08:15 local time on August 6, 1945 by the specially converted   bomber  piloted by Colonel , who later retired as a brigadier general in the .

Diplomats from 75 countries attended this anniversary including the United States, United Kingdom and France for the first time. United Nations secretary-general Ban Ki-moon, who was also attending this ceremony for the first time said "Together, we are on a journey from ground zero to global zero — a world free of weapons of mass destruction, and that is the only sane path to a safer world. For as long as nuclear weapons exist, we will live under a nuclear shadow."

U.S. Ambassador to Japan  also attended, marking the first time that a U.S. representative has attended the ceremony. Meanwhile, some conservatives in the United States have criticised the choice for Roos to attend. Gene Tibbets, the son of retired Brigadier General Tibbets said on ,  "It's making the Japanese look like they're the poor people, like they didn't do anything. They hit Pearl Harbor, they struck us. We didn't slaughter the Japanese. We stopped the war."

Three days after Hiroshima, another atomic bomb, "", was dropped on nearby . The Japanese Government surrendered unconditionally on August 15, and signed the formal surrender on the  on September 2 in .

Approximately 140,000 people died within days from the initial blast of the Hiroshima bomb and during the following year from radiation. The total death toll was almost half of Hiroshima's population.