Nagasaki is to hold a ceremony Monday to commemorate the 65th anniversary of the US atomic bombing of the Japanese port city, in which about 74,000 were killed, dpa reported.
Those at the ceremony are to observe a minute's silence in memory of victims of the attack at 11:02 am (0202 GMT), the moment of the blast 65 years ago.
The bombing, the second such attack in the closing days of World War II, injured about the same number in Nagasaki, which had a population at the time of 240,000.
Nagasaki is now a prosperous city with a population of more than 440,000 on the Japanese southern island of Kyushu.
Three days after the atomic bombing of Hiroshima, the second blast increased the pressure for Japan to surrender, which it did on August 15, 1945, six days after the Nagasaki bombing.
United Nations Secretary General Ban Ki Moon met victims of the atomic bombing Thursday during his first visit to Nagasaki. On Friday, Ban attended the Peace Memorial Ceremony in Hiroshima, which commemorated the atomic bombing of the western Japanese city on August 6, 1945. Ban was the first UN chief to participate in the annual event.
Representatives from more than 70 countries, including US Ambassador to Japan John Roos, attended Friday's ceremony in Hiroshima. Roos was the first US envoy to do so. Delegations from Britain and France, both nuclear powers, also joined in for the first time.