The two governments hope Obama's visit to Hiroshima, where a U.S. atomic bomb killed thousands instantly on August 6, 1945, and some 140,000 by the year's end, underscores a new level of reconciliation and tighter ties between the former enemies.
"We come to ponder the terrible force unleashed in the not so distant past," Obama said after laying a wreath at the peace memorial.
"We come to mourn the dead, including over 100,000 Japanese men, women and children, thousands of Koreans and a dozen Americans held prisoner. Their souls speak to us."
Before laying the wreath, Obama visited a museum where haunting displays include photographs of badly burned victims, the tattered and stained clothes they wore and statues depicting people with flesh melting from their limbs.
After speaking, Obama shook hands and chatted briefly with two atomic bomb survivors. Obama and Sunao Tsuboi, 91, smiled as they exchanged words; Shigeaki Mori, 79, cried and was embraced by the president.
