A presidential visit would be controversial in the United States if it were seen as an apology.
A majority of Americans view the bombing of Hiroshima on August 06, 1945, and of the city of Nagasaki three days later, as justified to end the war and save U.S lives. The vast majority of Japanese think the bombings were unjustified.
U.S. Secretary of State John Kerry said during a visit to the city this month that Obama wanted to travel there, though he did not know if the president`s schedule when he visited Japan for the May 26-27 summit would allow him to.
Hiroshima bombing survivors, and other residents, have said they hope for progress in ridding the world of nuclear weapons, rather than an apology, if Obama makes the historic visit.
Hopes for Obama`s visit to Hiroshima were raised after a speech in April 2009 in Prague when he called for a world without nuclear weapons. He later said he would be honoured to visit the two cities that suffered nuclear attack.
Kerry, who toured the Hiroshima Peace Memorial and Museum, called its haunting displays "gut-wrenching" and said everyone should visit.
The displays include photographs of badly burned victims, the tattered and stained clothes they wore and statues depicting them with flesh melting from their limbs.