US Secretary of State John Kerry will not say sorry for America's atomic bombing of Hiroshima when he visits a revered memorial.
A US official travelling with Mr Kerry to Japan ruled out an apology ahead of Monday's tour with other foreign ministers of the Peace Memorial Park and Museum in the city, where 140,000 Japanese died from the first of two atomic bombs dropped by America in the closing days of the Second World War.
Mr Kerry, who will be the most senior American government official to have visited the site, plans to lay flowers and is expected to express the sorrow that all feel upon reflection about the bombing - which was the first use of a nuclear weapon against an enemy in history.
The official said Mr Kerry intends to use the occasion to promote US President Barack Obama's vision of a nuclear-free world and the need to prevent proliferation of weapons of mass destruction.
Mr Obama has yet to decide whether he might visit Hiroshima and the memorial when he attends a Group of Seven meeting of leaders in central Japan in late May, according to the official.
The president said in an interview during his first year in office that he would be "honoured" to travel to Hiroshima.
For many years, top US officials avoided going to Hiroshima because of political sensitivities. Many Americans believe the dropping of atomic bombs in August 1945 were justified and hastened the end of the war.
Japanese survivors' groups have campaigned for decades to bring top officials from the US and other nuclear weapon states to see Hiroshima's scars as part of a grassroots movement to abolish nuclear weapons.
No serving US president has visited the site. It took 65 years for a US ambassador to attend Hiroshima's annual memorial service, and six more years to win Mr Kerry's visit.
The US official said Japan did not seek an apology from Mr Kerry, and that neither side is looking to reopen the question of blame for the various atrocities of the war.
Instead, he said both countries want the event to show the strong ties they have developed since peace in 1945 and their shared efforts to promote a peaceful world.
The museum includes harrowing images of the destruction and shocking exhibits, including the torn clothing of children who perished and skin, fingernails, deformed tongues and other horrible examples of the exposure to the blast and its residual radiation.
Some explanations mounted on the wall, however, do not align with the views of all historians and experts in the United States or elsewhere.
For example, one suggests that the United States used the weapon in part to justify the extraordinary costs of the Manhattan Project to develop it. Disagreements over motivations and possible justification rage among historians, ethicists and others to this day.