NAGASAKI (Kyodo) -- Nagasaki marked the 73rd anniversary of the U.S. atomic bombing of the city on Thursday, with its mayor calling for security policies not reliant on nuclear deterrence and pressing Japan to fulfill its "moral obligation" to lead efforts toward a nuclear-free world.
Nagasaki Mayor Tomihisa Taue, in his peace declaration, also urged the Japanese government to support an international nuclear ban treaty adopted last year.
"I hereby ask that the Government of Japan, the only country to have suffered from the wartime use of nuclear weapons, support the Treaty on the Prohibition of Nuclear Weapons and fulfill its moral obligation to lead the world towards denuclearization," Taue said.
For this year's ceremony, U.N. Secretary General Antonio Guterres became the first sitting chief of the international body to attend the annual event.
The declaration called on global leaders not to forget "the resolve" of the first U.N. General Assembly resolution to aim for the elimination of nuclear arsenals.
A moment of silence was observed at 11:02 a.m., when the plutonium-core atomic bomb "Fat Man" dropped by a U.S. B-29 aircraft exploded over Nagasaki on Aug. 9, 1945, in World War II. The atomic bomb, which followed one dropped on Hiroshima on Aug. 6, killed an estimated 74,000 in Nagasaki by the end of that year.
"To the great concern of those in the atomic-bombed cities, a shift towards openly asserting that nuclear weapons are necessary and that their use could lead to increased military might is once again on the rise," according to the declaration.
The ceremony comes amid expectations for progress on denuclearization.
The Nagasaki mayor said the atomic-bombed cities have great expectations for "irreversible denuclearization," urging the Japanese government to seize the opportunity to create a nuclear-free zone in Northeast Asia.
Representatives from 71 countries were expected to gather at the Peace Park where atomic bombing survivors and visitors prayed for lasting peace.
Guterres, in delivering a speech, called on all countries to commit to nuclear disarmament and make "visible" progress with urgency.
"Disarmament processes have slowed and even come to a halt," Guterres said as the adoption last year of the Treaty on the Prohibition of Nuclear Weapons demonstrated the frustration felt by many states.
The U.N. chief expressed solidarity with hibakusha, or atomic bombing survivors, who have among the leaders of peace and disarmament.
As the only nation to have come under nuclear attack, Japan has been backing the creation of a nuclear free world, and Prime Minister Shinzo Abe has vowed to make strenuous efforts toward the goal.
"In recent years, differences in the approaches of various countries on nuclear disarmament have become evident," Abe said in his speech.
Japan will serve as an intermediary between nuclear powers and non-nuclear states, Abe said, adding that an accurate understanding of the tragic realities of the atomic bombings and cooperation from both parties is essential.
As of March, the number of hibakusha stood at 154,859, with their average age at 82.06.