"May the prophetic voices" of the survivors of Hiroshima and Nagasaki "continue to serve as a warning to us and for coming generations," he said in a written message sent Aug. 6 to Hidehiko Yuzaki, governor of the Hiroshima prefecture, who led a peace memorial ceremony.

The pope also invited people to pray for a nuclear weapons-free world after reciting the Angelus Aug. 9.

Recalling "the tragic atomic bombardments" of Hiroshima and Nagasaki and his visit there in 2019, which stirred within him "deep emotion and gratitude," Pope Francis told visitors in St. Peter's Square, "I renew the invitation to pray and the commitment to a world completely free of nuclear weapons."

In 1945, during World War II, the United States dropped atomic bombs on Hiroshima Aug. 6 and on Nagasaki Aug. 9 in an effort to get Japan to surrender. The cities were decimated and, by year's end, at least 200,000 people had died from the blasts or the aftereffects.

Those who survived, called hibakusha, were honored at the Aug. 6 ceremony, and the pope greeted them as well as the organizers and others taking part in the ceremony.

The pope's message and others were published on the Hiroshima For Global Peace website: hiroshimaforpeace.com.

"I was privileged to be able to come in person to the cities of Hiroshima and Nagasaki during my apostolic visit in November last year, which allowed me to reflect at the peace memorial in Hiroshima and at Hypocenter Park in Nagasaki on the destruction of human life and property wrought in these two cities during those terrible days of war three-quarters of a century ago," the pope wrote.

"I continue to hold in my heart the longing of the peoples of our time, especially of young people, who thirst for peace and make sacrifices for peace. I carry, too, the cry of the poor, who are always among the first victims of violence and conflict," he said.

"It has never been clearer that, for peace to flourish, all people need to lay down the weapons of war, and especially the most powerful and destructive of weapons: nuclear arms that can cripple and destroy whole cities, whole countries," the pope said.

Reiterating what he said in Hiroshima in 2019, Pope Francis wrote that the use of atomic energy for war and the possession of nuclear weapons are both "immoral."

The pope ended his message with "abundant divine blessings" for all those commemorating on this "solemn anniversary."