Victims of the atomic bombings of Japan want an apology from US President Barack Obama when he visits Hiroshima next week, the head of a survivors' group said Thursday.
Obama will become the first sitting US president to visit Hiroshima, where the first atomic bomb was dropped on August 6, 1945, killing about 140,000 people in total.
Tens of thousands were killed by the fireball that the powerful Hiroshima blast generated, with many more succumbing to injuries or illnesses caused by radiation in the weeks, months and years afterwards.
Vast swathes of the city, including many of its military and industrial installations, were flattened.
The southern city of Nagasaki was hit by a second bomb days later, killing 74,000 people, in one of the final acts of World War II.
"I urge him to apologise to those who died, bereaved families and parents who lost their children," Terumi Tanaka, secretary general of the Japan Confederation of A- and H-Bomb Sufferers Organizations and a survivor of the Nagasaki explosion, told reporters.
The comments came as Obama's much anticipated journey to Hiroshima reignited an emotional debate over whether the bombings were justified and whether the US president should apologise.
Obama, who will be in Japan for a Group of Seven summit, will visit Hiroshima's Peace Memorial Park on May 27 and be accompanied by Japanese Prime Minister Shinzo Abe.
US officials have ruled out an apology for the bombings and said Obama will not revisit the decision by then-US President Harry Truman to carry them out.
"Many atomic bomb victims think it's not all right if (Obama) doesn't apologise," said Toshiki Fujimori, the group's assistant secretary general and also a survivor of the Hiroshima bomb.
"Atomic bomb victims are demanding that it be made clear that the dropping of atomic bombs was inhumane and breaches international law, and that will be confirmed by his apology."
Obama has been vocal on nuclear issues since becoming president in 2009 and made a landmark speech in Prague in April of that year calling for the elimination of nuclear weapons.
Last month US Secretary of State John Kerry laid a wreath near the building, and visited the "gut-wrenching" memorial museum that shows the human cost of the bombing.
Japan has long urged world leaders to visit Hiroshima and Nagasaki to see the horrors of the atomic bombings and join efforts to eradicate nuclear arms.
Former president Jimmy Carter visited Hiroshima after leaving office, while Richard Nixon went to the city a few years before assuming the presidency.