Tokyo, Aug 6 (IANS): Japan on Monday marked the 73rd anniversary of the US atomic bombing of Hiroshima during the Second World War, with the city's Mayor making a fresh call for a world without nuclear weapons through dialogue.

Mayor Kazumi Matsui warned of the re-emergence of tensions over nuclear weapons seen during the Cold War and sought rational actions by global leaders, reports The Japan Times.

"If the human family forgets history or stops confronting it, we could again commit a terrible error," Matsui said at a memorial ceremony.

Japan needs to lead the international community toward "dialogue and cooperation for a world without nuclear weapons", the mayor added.

At the Peace Memorial Park, a moment of silence was observed at 8.15 a.m., when the "Little Boy" uranium-core atomic bomb dropped by a US bomber exploded above Hiroshima on August 6, 1945.

It killed an estimated 140,000 people by the end of that year.

The 73rd anniversary comes after Pyongyang's promise of a complete denuclearization of the Korean Peninsula grabbed attention following the historic US-North Korean summit in June.

Matsui expressed hope that the easing of tensions on the Korean Peninsula will continue through dialogue and called on global leaders to make an international treaty comprehensively prohibiting nuclear weapons a "milestone" toward the goal of ridding the world of nuclear arsenals.

Prime Minister Shinzo Abe, attending the memorial ceremony, pledged that Japan will try to bridge nuclear powers and non-nuclear states and lead international efforts.

"Maintaining its three nonnuclear principles, our country is determined to make strenuous efforts to serve as a bridge between both parties," Abe said.

As of March, the number of 'hibakusha' or atomic bomb survivors stood at 154,859.

Their average age is now just over 82.

UN Secretary-General Antonio Guterres said in his message the legacy of Hiroshima is one of "resilience" and sought continued moral support from the 'hibakusha'.