Pope Francis has called on world leaders scrap nuclear weapons.
During a visit to Nagasaki, where the second of two US atomic bombs fell on Japan in 1945, the pontiff said the arms race decreases security and wastes resources.
He said nuclear weapons threaten humanity with catastrophic destruction.
He said the Nagasaki memorial stands as a stark reminder “of the pain and horror that we human beings are capable of inflicting upon one another.”
After laying a wreath at Ground Zero in the city, the pope said he is convinced that a “world without nuclear weapons is possible and necessary.”
“I ask political leaders not to forget that these weapons cannot protect us from current threats to national and international security.”
The pope visited both Nagasaki and Hiroshima at the start of his three-day visit to Japan, which is aimed at emphasising his call for a global ban on atomic weapons.
“Peace and international stability are incompatible with attempts to build upon the fear of mutual destruction or the threat of total annihilation,” he said.
“They can be achieved only on the basis of a global ethic of solidarity and cooperation.
“In a world where millions of children and families live in inhumane conditions, the money that is squandered and the fortunes made through the manufacture, upgrading, maintenance and sale of ever more destructive weapons are an affront crying out to heaven.”
The first US atomic bomb killed 140,000 people in Hiroshima on August 6th 1945.
The second one dropped on Nagasaki three days later killed another 74,000 by the end of the same year.