HIROSHIMA, Japan (AP) — Hiroshima on Wednesday marked the 80th anniversary of the U.S. atomic bombing of the western Japanese city, with many aging survivors expressing frustration about the growing support of global leaders for nuclear weapons as a deterrence.

With the number of survivors rapidly declining and their average age now exceeding 86, the anniversary is considered the last milestone event for many of them.

“There will be nobody left to pass on this sad and painful experience in 10 years or 20 years,” Minoru Suzuto, a 94-year-old survivor, said after he kneeled down to pray at the cenotaph. “That’s why I want to share (my story) as much as I can.”

The bombing of Hiroshima on Aug. 6, 1945, destroyed the city and killed 140,000 people. A second bomb dropped three days later on Nagasaki killed 70,000. Japan surrendered on Aug. 15, ending World War II and Japan’s nearly half-century of aggression in Asia.

Hiroshima Mayor Kazumi Matsui warned against a growing acceptance of military buildups and of using nuclear weapons for national security amid Russia’s war in Ukraine and conflicts in the Mideast, with the United States and Russia possessing most of the world’s nuclear warheads.

“These developments flagrantly disregard the lessons the international community should have learned from the tragedies of history,” he said. “They threaten to topple the peacebuilding frameworks so many have worked so hard to construct.”

He urged younger generations to recognize that such “misguided policies” could cause “utterly inhumane” consequences for their future.

“We don’t have much time left, while we face a greater nuclear threat than ever,” said Nihon Hidankyo, a Japanese grassroots organization of survivors that won the Nobel Peace Prize last year for its pursuit of nuclear abolishment.

“Our biggest challenge now is to change, even just a little, nuclear weapons states that give us the cold shoulder,” the organization said in its statement.

About 55,000 people, including representatives from a record 120 countries and regions, including Russia and Belarus, were expected to attend the ceremony. A minute of silence was held while a peace bell rang out at 8:15 a.m., the time when a U.S. B-29 dropped the bomb on the city.

Japanese Prime Minister Shigeru Ishiba, the city’s mayor and other officials laid flowers at the cenotaph. Dozens of white doves, a symbol of peace, were released after the mayor’s speech.

Hours before the official ceremony, as the sun rose over Hiroshima, survivors and their families started paying tribute to the victims at the peace memorial park.

Kazuo Miyoshi, a 74-year-old retiree, came to honor his grandfather and two cousins who died in the bombing and prayed that the “mistake” will never be repeated.

“We do not need nuclear weapons,” Miyoshi said.

“There is hope,” U.N. Secretary General Antonio Guterres said in a statement read by Izumi Nakamitsu, U.N. Under-Secretary-General and High Representative for Disarmament Affairs, noting Nihon Hidankyo’s Nobel Peace Prize and countries’ re-commitment to a nuclear free world in “the Pact for the Future” adopted last year.

Guterres stressed the importance to carry forward the survivors’ testimony and message of peace and added: “Remembering the past is about protecting and building peace today and in the future.”

Wednesday’s anniversary comes at a time when possession of nuclear weapons for deterrence is increasingly supported by the international community, including Japan.

Some survivors said they were disappointed by President Donald Trump’s recent remark justifying Washington’s attack on Iran in June by comparing it to the atomic bombing of Hiroshima and Nagasaki, and the mild response from the Japanese government.

“It’s ridiculous,” said Kosei Mito, a 79-year-old former high school teacher who was exposed to radiation while he was still in his mother’s womb. “I don’t think we can get rid of nuclear weapons as long as it was justified by the assailant.”

In the Vatican, Pope Leo XIV said Tuesday that he was praying that the 80th anniversary of the atomic bomb on Hiroshima “will serve as a call to the international community to renew its commitment to pursuing peace for our own human family.”

Japan’s government has rejected the survivors’ request to sign the Treaty on the Prohibition of Nuclear Weapons or attend its meetings as observers because it is under the protection of the U.S. nuclear umbrella.

Matsui, the city’s mayor, in his speech Wednesday, urged Japan’s government to sign and ratify the nuclear weapons ban treaty.

Ishiba, in a speech, reiterated his government’s pledge to work toward a world without nuclear weapons, but did not mention the treaty and again indicated his government’s support for nuclear weapons possession for deterrence.

Past prime ministers have stressed Japan’s status as the world’s only country to have suffered nuclear attacks and have said Japan is determined to pursue peace, but survivors say it’s a hollow promise.

The Japanese government has only paid compensation to war veterans and their families, even though survivors have sought redress for civilian victims. They have also sought acknowledgment by the U.S. government of its responsibility for the civilian deaths.

Associated Press video journalist Ayaka McGill contributed to this report.