Japan is the only country to have come under nuclear attack
Shinzo Abe said existing non-proliferation treaties should be strengthened, and pledged Japan would make “utmost efforts for the realisation of eternal world peace”.
The country was marking the date more than seven decades since the US dropped an atomic bomb on Hiroshima, which detonated 600 metres above the city, killing 140,000 and effectively ending the Second World War.
The event at Peace Memorial Park, near Hiroshima’s ground zero, was attended by 50,000 people and representatives from 80 nations and the EU, according to The Japan Times.
However, the commemoration has been overshadowed by the escalating threat posed by North Korea.
Last month its military tested two intercontinental ballistic missiles with major US cities such as Los Angeles and Chicago within range of attack, though it is unclear if they could be armed with nuclear warheads.
“This hell is not a thing of the past,” Hiroshima Mayor Kazumi Matsui said at Sunday’s commemoration ceremony. “As long as nuclear weapons exist and policymakers threaten their use, their horror could leap into our present at any moment.
“You could find yourself suffering their cruelty.”
If a nuclear bomb was dropped today it could cause greater damage than the Hiroshima bomb combined with the one dropped on the city of Nagasaki three days later, he added.
Japan is the only country to have come under nuclear attack, and uses the “never again” mantra to come to terms with the impact of the two bombs dropped in August 1945.
Article 5 of the country’s constitution renounces war, and states that “land, sea, and air forces, as well as other war potential, will never be maintained”.
But when asked whether Japan should acquire the means to strike North Korean missile sites, Mr Abe did not reject the idea of a pre-emptive strike.
Japan currently relies on allies such as the US for nuclear deterrence, and refused to ratify or negotiate a landmark UN Treaty on the Prohibition of Nuclear Weapons last month.
When Barack Obama became the first US President to visit Hiroshima last year, Donald Trump criticised his call for an end to nuclear weapons and suggested he bring up Japan’s 1941 attack on the US naval base at Pearl Harbour instead.