TOKYO - Survivors of the 1945 U.S. atomic bombings of Hiroshima and Nagasaki and their mayors expressed disappointment Saturday after a review conference for the nuclear nonproliferation treaty ended yet again without a consensus document.

Officials participating in the monthlong conference in New York failed to overcome disagreements Friday chiefly over the Iranian nuclear program, despite the conference president negotiating with countries including Iran and the United States, one of the five nations allowed to possess nuclear weapons under the treaty.

"It's extremely regrettable," Jiro Hamasumi, secretary general of Nihon Hidankyo, Japan's leading group of atomic bomb survivors, said in an online press conference.

Hamasumi, an 80-year-old who experienced the atomic bombing of Hiroshima on Aug. 6, 1945 while inside his mother's womb, delivered a speech at a nongovernmental organization session of the conference aimed at reviewing the implementation of the Nuclear Non-Proliferation Treaty.

On the sidelines of the conference, Nihon Hidankyo, the recipient of the 2024 Novel Peace Prize, held an exhibition at the U.N. headquarters to show the devastation caused by the atomic bombings.

Nagasaki Mayor Shiro Suzuki also expressed his "strong disappointment."

"I'm deeply resentful that the signatory nations of the treaty failed to show their resolve to realize a world without nuclear weapons sincerely," Suzuki told reporters.

Hiroshima Mayor Kazumi Matsui said in a statement that it was "extremely regrettable" that no outcome document was released due to outstanding differences among the participating nations.

The attack on Hiroshima, western Japan, in the final stages of World War II killed an estimated 140,000 people by the end of 1945.

Another atomic bomb dropped on Nagasaki on Aug. 9, three days after Hiroshima, is believed to have killed around 74,000 in the southwestern Japan city by the end of that year.

Besides the United States, Britain, China, France and Russia are allowed to possess nuclear weapons under the treaty that entered into force in 1970.

A revised draft final document that was circulated earlier mentioned Iran's nonproliferation obligations, prohibiting the country from seeking, developing or acquiring nuclear weapons.

Japanese Foreign Minister Toshimitsu Motegi said while it was "extremely regrettable" that the meeting had ended without a final document, the NPT, which involves both nuclear and non-nuclear weapons states, was reaffirmed as the cornerstone of the nuclear disarmament and nonproliferation regime.

"As divisions within the international community over nuclear disarmament continue to deepen, it remains crucial to maintain and strengthen the NPT," Motegi said, adding Japan will continue to aim for "realistic and practical" efforts toward a nuclear-free world.

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