Inside Hiroshima's Peace Park, tens of thousands of survivors, relatives, government officials and diplomats observed the 67th anniversary Monday of the city's atomic bombing, while just outside others marked the occasion by loudly protesting the decision to reactivate two nuclear reactors.

About 50,000 people, including Prime Minister Yoshihiko Noda, Foreign Minister Koichiro Genba and the heads of the Lower and Upper houses, Takahiro Yokomichi and Kenji Hirata, took part in the annual Hiroshima Peace Memorial Ceremony, organizers said.

Noda told those on hand that the calamity 67 years ago must never be forgotten and vowed Japan would act to ensure a nuclear-free world.