Pope Francis has made an impassioned appeal for the abolition of nuclear weapons during a visit to Nagasaki, one of the two Japanese cities targeted by atomic bombs during World War Two.
He decried the "unspeakable horror" of nuclear weapons and insisted they were "not the answer" for global peace.
At least 74,000 were killed in Nagasaki by the attack by US forces in 1945.
Two survivors of the bombing, now both in their 80s, presented the pontiff a wreath during the Sunday service.
Pope France arrived from Thailand on Saturday for a four-day visit, which is only the second papal visit to Japan.
Hundreds of people gathered in the pouring rain to hear him in Nagasaki. The Pope then attended a meeting at the Peace Memorial in Hiroshima, the site of the other atomic attack.
In a sombre ceremony, the Pope unequivocally condemned the use of nuclear weapons.
"This place makes us deeply aware of the pain and horror that we human beings are capable of inflicting upon one another," he said at the event in Nagasaki.