Doves fly over the Peace Memorial Park with a view of the gutted A-bomb dome at a ceremony in Hiroshima August 6, 2007, on the 62nd anniversary of the world's first atomic bombing on the city. [Photo: Reuters]

Around 45,000 Hiroshima citizens and peace wishers around the world observed a minute of silence in Hiroshima at 8:15 a.m. Monday (2315 GMT), the time when U.S. dropped an atomic bomb 62 years ago.

"Hiroshima was a hell where those who somehow survived envied the dead," Hiroshima mayor Tadatoshi Akiba said at the memorial ceremony. He called for non-proliferation measures to be taken around the global to avoid such catastrophes.

"...the message born of that agony is a beam of light now shining the way for the human family," Akiba said in a peace declaration. The atomic bomb survivors "have continuously spoken of experiences they would rather forget, and we must never forget their accomplishments in preventing a third use of nuclear weapons, " he said.

In an address at the ceremony, Prime Minster Shinzo Abe vowed to stick to Japan's non-nuclear principles of not producing, possessing or allowing the entry into its territory of nuclear weapons.

"I pledge afresh that I will continue to abide by provisions of the Constitution, honestly aspire for international peace and firmly maintain the three non-nuclear principles," he said.

On Sunday, Abe met several local groups of atomic bomb survivors in Hiroshima and apologized for the controversial remarks by former Defense Minster Fumio Kyuma which seemed to justify U.S. bombing, Kyodo News said. Kyuma quit as defense minister in early July after saying in a speech that "I understand the bombing brought the war to its end. I think it was something that couldn't be helped."

U.N. Secretary General Ban Ki Moon said in a message read on his behalf by High Representative for Disarmament Sergio de Queiroz Duarte that "We must do all we can to turn back the tide of nuclear proliferation."

A nuclear bomb was detonated over Hiroshima at an altitude of some 600 meters at the end of World War Two, killing an estimated 140,000 people in 1945. A second atomic bomb was dropped on Nagasaki on Aug. 9, 1945 and Japan surrendered six days later.