Nagasaki has marked the 70th anniversary of the atomic bombing attack on Sunday, August 9.
Speeches at the ceremony criticized the attending PM Shinzo Abe for his plans to loosen the restrictions on what Japan’s military can do.
At least 70,000 people died in the US forces attack, which came three days after another bomb was dropped on Hiroshima.
Nagasaki was only chosen after a cloud obscured the original target, Kokura.
A solemn ceremony in front of guests from 75 countries, including US ambassador Caroline Kennedy, began with a declaration read out by children.
Nagasaki mayor Tomihisa Taue then delivered a peace declaration to the ceremony. He said there was “widespread unease” about PM Shinzo Abe’s bid to alter the country’s pacifist constitutional.
A survivor of the Nagasaki attack, 86-year-old Sumiteru Taniguchi, described the injuries he had suffered and said he could not accept Shinzo Abe’s new legislation.
The legislation would allow Japan to engage in combat – in defense of an ally which comes under attack – for the first time since World War Two.
In his address to the ceremony, PM Shinzo Abe said Japan remained “determined to pursue a world without nuclear weapons”.
In a statement read out on his behalf, UN Secretary General Ban Ki-moon said: “Nagasaki must be the last – we cannot allow any future use of nuclear weapons. The humanitarian consequences are too great. No more Nagasakis. No more Hiroshimas.”
The effects of the atomic bomb were instant and devastating. It destroyed a third of the city, killing thousands instantly and condemning more to death from radiation sickness.
Days later, Japan surrendered, ending World War Two, although the necessity of the two bombs has been debated ever since.