Tokyo, Aug 9 (IANS): The Japanese city of Nagasaki on Tuesday commemorated the 71st anniversary of the atomic bombing that killed thousands of people towards the end of the World War II.

The ceremony began at 10.35 a.m. As the Peace Bell tolled, a minute of silence was observed at 11.02 a.m., the exact time when the atomic bomb code-named 'Fat Boy' dropped by the US war planes, exploded over the city on this day in 1945, Efe news reported.

Three days earlier, on August 6 the US war planes dropped the first atomic bomb to be used in human history on the Japanese city of Hiroshima. That devastating mass killer was code named "Little Boy".

Following the ceremony, Japanese Prime Minister Shinzo Abe and Nagasaki Mayor Tomihisa Taue spoke about the importance of US President Barack Obama's historic visit to Hiroshima earlier in May and called for an end to nuclear proliferation.

Abe said the US leader's visit and his message of peace in Hiroshima brings hope to those, in Japan as well as in other countries, who believe in a world free of nuclear weapons.

Saying "we must not allow a repeat" of the tragedy that hit Hiroshima and Nagasaki 71 years ago, he added that as the only country to have suffered a nuclear bomb attack, Japan is going to make all possible efforts to bring about a globally-ratified Nuclear Non-proliferation Treaty.

The US had launched the world's first-ever nuclear attack by detonating an atom bomb over the city of Hiroshima on August 6, 1945, and followed it up with a second similar attack on Nagasaki, prompting Japan to surrender on August 15, and bringing the War to an end.

The bomb, dropped on the valley in the northern, industrial part of this port city, instantly killed around 74,000 people, while thousands more succumbed to the after-effects of radiation in subsequent years.

Hiroshima and Nagasaki are the only cities in the world to have suffered a nuclear bomb attack.

In March, there were a total 174,080 'hibakushas' (bombing survivors, as they are collectively known in Japan) in Hiroshima and Nagasaki, as compared to 372,264 in 1980, and their average age was 80 years.