Pope Francis has called the use of atomic energy for military purposes a "crime" in Hiroshima, where he addressed his message calling for the elimination of nuclear weapons amid a meeting with survivors of the attack on the Japanese city in 1945.

The visit comes hours after an important symbolic station in the city of Nagasaki, where the Pope attacked all types of nuclear weapons, including those used as a deterrent.

At least 140,000 people were killed after the United States dropped an atomic bomb on Hiroshima in 1945, while 74,000 were killed by a second bomb dropped on Nagasaki three days later.

"In less than a moment, a black hole devoured everything from destruction and death," said the pope near the "Peace Monument" in Hiroshima.

He stressed that "the use of atomic energy for military purposes today, more than ever, is a crime not only against human rights and dignity, but the right of any possible future for our common home."

Francesco at the "Peace Monument" in Hiroshima (Reuters)

The memory of the victims
The Pope signed a notebook to commemorate the victims, whom he said would live with "grief in solidarity" with them, amid warm applause from the audience.

He clung to the hands of a number of elderly survivors, who were overwhelmed by emotion when they met the 82-year-old Pope, who told them their horrible testimonies.

Francesco has made the call for a world without nuclear weapons the main focus of his four-day visit to Japan, starting from the two cities that are the most prominent witness in the world on nuclear atrocities.

He said he felt "the need to come here as a pilgrim for peace" and praised the "strength and dignity" of those who survived the attack.

As he did in Nagasaki earlier today, the Pope laid a wreath of white flowers in honor of the victims and bowed his head to pray before a moment of meditation, while the bells rang in honor of those who died in the disaster.

Survivors of the Hiroshima attack described the Pope's experiences, expressing support for his message to get rid of these weapons.

Among them was Yoshiko Kagimoto, who was 24 when the attack took place.

"People walking side by side like ghosts," she recalled. "No one in the world can imagine such a hell."

Survivors expressed concern about the disappearance of the memory of the attacks after their departure, and some hope that the Pope will again highlight the events they witnessed.

Nuclear bomb survivors meet with Pope in Hiroshima (Reuters)

Transfer the tragedy experience
"I think the transfer of the Hiroshima experience to future generations is the last task entrusted to us as bomb survivors," Koji Hosokawa told the Pope in a testimony read as he could not attend by himself.

The "Great Pontiff" (Francesco) in Hiroshima stressed that there is no place in the world for nuclear weapons, not even as a means of deterrence.

His position marks a shift from his predecessors. In a 1982 address to the United Nations, Pope John Paul II considered nuclear deterrence an inevitable evil.

"How can we propose peace while always resorting to the threat of nuclear war as a legitimate haven for conflict resolution? Real peace can only be unarmed," Francesco said.

In Nagasaki, he denounced the weapons industry, describing the money being spent on it as a "disgrace."

The Pope will return on Sunday night to Tokyo, where he will meet Monday victims of the "triple disaster" in Japan: earthquake, tsunami and leakage of radioactive materials in 2011.

He is scheduled to hold a mass at a baseball stadium in Tokyo, meet the new emperor Naruhito and hold talks with government officials and local Catholic leaders.