ABC: 06/07/2010
US attends Hiroshima ceremony for first time
Each year Japan invites the United States to attend a memorial ceremony marking the event and each year the US has declined to send a representative.
But in a first, the US sent a diplomatic representative to this year's ceremony that took place today.
It is also the first time a United Nations secretary-general has attended.
US ambassador John Roos was present at the ceremony and was joined by UN secretary-general Ban Ki-moon.
Mr Ban said the ceremony was highly emotional.
"I was so moved, so sad when I met some of the survivors," he said.
"We had to help them to realise their aspiration and dream to see during their limited lifetime, a world free of nuclear weapons."
Mr Ban has expressed his hope that nuclear weapons will never be used again.
"I have made nuclear disarmament and non-proliferation a top priority for the United Nations," he said.