Hiroshima, August 6 (RHC)-- Seven decades after the U.S. military’s deadly atomic bombing of the Japanese cities of Hiroshima and Nagasaki, survivors still recall horrors and suffer from the after-effects of the tragedy.

In Hiroshima this morning, church bells tolled at exactly 8:15 a.m. local time, as a solemn crowd marked 70 years since the United States dropped the world’s first atomic bomb on the city. Hiroshima Mayor Kazumi Matsui marked the anniversary by calling for the abolition of nuclear weapons.

During the final stage of the World War II, the U.S. dropped the world's first deployed atomic bombs on Hiroshima and Nagasaki on August 6 and 9, 1945, respectively, killing more than 200,000 people instantly.

In one instant, the atomic bombing killed around 140,000 people in Hiroshima, including those who died of radiation exposure or succumbed to their wounds. The mushroom cloud produced by the nuclear explosion rose to over 60,000 feet in about 10 minutes.

Sunao Tsuboi is 90 years old and recalls the moment when a B-29 bomber of the U.S. Air Force dropped a uranium bomb with a destructive force equivalent to 16 kilotons of TNT on Hiroshoma. Tsuboi was 20 years old on that day and still remembers the moment of impact: “It was a white, silvery flash,” said Sunao Tsuboi. He added: “I don’t know why I survived and lived this long. The more I think about it... the more painful it becomes to recall.”

Three days after the bombing of Hiroshima, the U.S. military dropped a plutonium bomb on the port city of Nagasaki, killing some 74,000 people. In the months and years to come, the world’s first nuclear attacks also left thousands of survivors to slow and agonizing deaths from burns and radiation sickness.

Today, 70 years later, residents of Hiroshima are begun holding ceremonies to mark the 70th anniversary of the US atomic attack on their city. People paid visits Hiroshima’s Peace Memorial Park to pray for victims of the atomic bombing.