"It seems to me that he does not fully understand the reality of the atomic bombings, which, if used, take the lives of many innocent citizens, regardless of whether they were friend or foe, and threaten the survival of the human race," Mayor Kazumi Matsui told reporters.

"I wish that President Trump would visit the bombed area to see the reality of the atomic bombing and feel the spirit of Hiroshima, and then make statements," Kazumi said.

The United States dropped an atomic bomb on Hiroshima on August 6, 1945 and then another on Nagasaki three days later. Shortly afterwards, Japan surrendered, ending World War II.

Around 140,000 people died in Hiroshima and about 74,000 others in Nagasaki, including many from the effects of radiation exposure. It was the only time that atomic weapons were used in warfare.

On June 22, following days of Israeli strikes on the Islamic republic, the United States bombed Iranian nuclear facilities.

Soon afterwards, Iran and Israel agreed a ceasefire, ending their 12-day war.

"I don't want to use an example of Hiroshima, I don't want to use an example of Nagasaki, but that was essentially the same thing," Trump said last Wednesday.

"That ended that war and this ended (this war)," Trump said at a NATO summit in The Hague.

His comments prompted anger from survivors and a small demonstration in Hiroshima. Last week, the city's assembly passed a motion condemning remarks that justify the use of atomic bombs.

Japan's atomic bomb survivors' group Nihon Hidankyo won the Nobel Peace Prize last year, and while accepting the prize, called on countries to abolish the weapons.