Pope Francis demanded world leaders renounce atomic weapons and the Cold War era doctrine of deterrence, saying the stockpiling of nuclear arms decreases security, wastes money and threatens humanity.

The Pope criticised the demise of arms control treaties while visiting Nagasaki, the site of the second of the two 1945 US atomic bombings on Japan.

After laying a wreath of flowers and praying at the foot of the memorial to the victims, the Pope said the place stands as a stark reminder “of the pain and horror that we human beings are capable of inflicting upon one another”.

“Convinced as I am that a world without nuclear weapons is possible and necessary, I ask political leaders not to forget that these weapons cannot protect us from current threats to national and international security,” he said.

The mood was sombre and silent, darkened by the downpour that drenched the terraced fields and rice paddies of Nagasaki as thousands of Japanese people came out in plastic raincoats to witness the second Pope to pay his respects to victims of the bomb.

The bombing of Nagasaki Show all 5 1 /5 The bombing of Nagasaki The bombing of Nagasaki Yosuke Yamahata's photographs of Nagasaki the day after the atomic bombing An arch is the sole landmark following the attack Image copyright Shogo Yamahata, provided courtesy of Bonhams The bombing of Nagasaki Yosuke Yamahata's photographs of Nagasaki the day after the atomic bombing The city is unrecognisable Image copyright Shogo Yamahata, provided courtesy of Bonhams The bombing of Nagasaki Yosuke Yamahata's photographs of Nagasaki the day after the atomic bombing Survivors wander through the desecrated landscape Image copyright Shogo Yamahata, provided courtesy of Bonhams The bombing of Nagasaki Yosuke Yamahata's photographs of Nagasaki the day after the atomic bombing A mother and her child appear in a state of shock Image copyright Shogo Yamahata, provided courtesy of Bonhams The bombing of Nagasaki Yosuke Yamahata's photographs of Nagasaki the day after the atomic bombing A woman breastfeeds her baby amid the rubble Image copyright Shogo Yamahata, provided courtesy of Bonhams

The Pope visited Nagasaki, and later Hiroshima, at the start of his three-day trip to Japan aimed at emphasising his call for a global ban on atomic weapons.

Nagasaki was the perfect place to begin his visit, the birthplace of Christianity in Japan and ground zero of the bomb.

The Holy See was among the first countries to sign and ratify the new UN nuclear prohibition treaty, and the Pope himself has gone further than any Pope before him in saying not only the use, but the mere possession of atomic weapons is “to be condemned”.

While the Pope did not repeat his 2017 condemnation on Sunday, he made a similar point.

“One of the deepest longings of the human heart is for security, peace and stability,” he said.

“The possession of nuclear and other weapons of mass destruction is not the answer to this desire; indeed they seem always to thwart it.”

The first US atomic bomb fell on Hiroshima on 6 August 6 1945, killing an estimated 140,000 people.

The second one dropped three days later on Nagasaki and killed another 80,000 by the end of the same year.

Many of the survivors have suffered the lasting impact of radiation and developed various forms of cancer.

Under the 1957 government law designed to support A-bomb survivors, or “hibakusha”, more than 370,000 people were recognised as eligible for various types of government support, including medical and welfare assistance, depending on how far they were from ground zero.

“In a world where millions of children and families live in inhumane conditions, the money that is squandered and the fortunes made through the manufacture, upgrading, maintenance and sale of ever more destructive weapons, are an affront crying out to heaven,” the Pope said.

Pope Francis arrives for a Holy Mass at Nagasaki’s baseball stadium (Getty) (Getty Images)

He lamented the “climate of distrust” that is eating away at non-proliferation efforts and the arms control framework, a reference to a series of violated treaties and the demise this year of the Intermediate-range Nuclear Forces (INF) treaty, a landmark Cold War-era arms control agreement.

The US formally withdrew from the treaty in August, after accusing Moscow of developing a Russian missile system prohibited under it.

Gerald Powers, director of the Catholic Peacebuilding Network at the University of Notre Dame’s Kroc Institute, said the Pope did not break any new ground on the morality of deterrence in his Sunday remarks, after he shifted the church’s position in 2017.

“Instead, the Pope reinforces the church’s long-standing efforts to delegitimise the nuclear status quo and convince the world that nuclear disarmament is not only a moral imperative but should be a policy goal,” he said in an email.

Starting 1982, St John Paul II said nuclear deterrence could be morally acceptable in the interim “so long as it is used as a step toward mutual, verifiable nuclear disarmament”.

But the Holy See has come to realise in recent years that the policy was becoming a permanent condition, and not leading to disarmament.

By condemning nuclear deterrence, the Pope pleased liberals and agitated conservatives, perhaps informing his more nuanced remarks on Sunday.

After the bombs dropped: Hiroshima and Nagasaki Show all 19 1 /19 After the bombs dropped: Hiroshima and Nagasaki After the bombs dropped: Hiroshima and Nagasaki 424444.bin After the bombs dropped: Hiroshima and Nagasaki 424445.bin Hiroshima: Cap of a mobilised student 2,200m from the hypocentre Tetsuo Manabe was a second-year student at a junior high school. He was exposed to the A-bomb while guarding his school as a member of a school defence squad, which comprised first and second-year students living in the neighbourhood. He was treated at a relief station, but died the following month. Donated by Mitsuko Yoshioka After the bombs dropped: Hiroshima and Nagasaki 424488.bin Hiroshima: A wrist watch One of the many clocks which stopped immediately after the A-bomb went off on August 6 1945. After the bombs dropped: Hiroshima and Nagasaki 424462.bin Hiroshima: Lunchbox (Replica) 550m from the hypocentre Reiko Watanabe (then 12) was a first-year student at First Municipal Girls' High School. She was exposed to the A-bomb during building demolition work. This lunchbox was found later near the work site, but her body was never found. The contents of the box, which Reiko never ate, were scorched black. Approximately 7,200 of the mobilised students in Hiroshima were killed by the atomic bomb. Donated by Shigeru Watanbe After the bombs dropped: Hiroshima and Nagasaki 424446.bin Hiroshima: Student's shirt 500m from the hypocentre Mutsuko Shimogouchi, a third-year student at Shintoku Girls' High School, was on the road in front of Shirakami Shrine when she was exposed to the A-bomb. Seriously burnt on her face, she soaked herself in a river for a while to ease the unbearable heat. On the way home, she was briefly treated at a primary-school-turned-temporary-rescue-station. She reached home in the evening of the same day with her face covered by gauze. She could be identified only by the name tag sewn onto the left side of her blouse. Two days later, she passed away. Donated by Chizuno Shimogouchi After the bombs dropped: Hiroshima and Nagasaki 424449.bin Nagasaki: Blouse made of summer Kimono cloth 800m from the hypocentre Miyako Tanube was exposed at Keiho Junior High School and died on the morning of 16th August, seven days after the bombing. On the day of the bombing, Miyako wore this blouse, which she made herself from her mother's summer kimono (a traditional Japanese garment). Her mother had to tear the left side of the blouse off Miyako's body because she was disabled by the serious burns and a bone fracture that she had suffered. Donated by Fuji Tanabe After the bombs dropped: Hiroshima and Nagasaki 424464.bin Hiroshima: Exposed plates 700m from the hypocentre This plate was found in the rubble near to the city centre. Some white substance is fused with the plate from the heat rays of the atomic bomb. After the bombs dropped: Hiroshima and Nagasaki 424454.bin Nagasaki: Exposed roof tile The surface of ceramic roof tiles exposed directly to the flash of heat instantly boiled and then hardened, leaving a distinctive bubbled texture. The bubbling was greater the shorter the distance from the hypocentre, reflecting the unimaginable ferocity of the atomic bomb heat rays. After the bombs dropped: Hiroshima and Nagasaki 424463.bin Nagasaki: Deformed glass container 350m from the hypocentre This glass container was donated in memory of a young girl who died after the bomb dropped. Her parents' house was 350 metres from the hypocentre. Her father, who was out at the time, survived, but her mother perished. Donated by Matsu Ogasawara After the bombs dropped: Hiroshima and Nagasaki 424450.bin Nagasaki: Rosary 500m from the hypocentre At the time of the explosion, more than ten parishioners were attending a mass in the chapel of Urakami Cathedral. All of them were trapped under the building and killed instantly. This rosary was with one of the parishioners. Donated by Ichiro Fukahori After the bombs dropped: Hiroshima and Nagasaki 424481.bin Nagasaki: Melted crucifix This melted crucifix was unearthed during the construction of a house in the region. After the bombs dropped: Hiroshima and Nagasaki 424441.bin Hiroshima: Pocket Watch (Replica) 1,600m from the epicentre Kengo Nikawa (then 59) was exposed to the A-bomb while heading for his assigned building demolition site in the city centre, where work was being carried out to create a fire lane to prevent the spread of fire in the event of an air raid. Burned from his right shoulder to his back and head, he died on August 22nd. This watch, a treasured gift from his son Kazuo, stayed with him whenever he went. Donated by Kazuo Nikawa After the bombs dropped: Hiroshima and Nagasaki 424482.bin Hiroshima: Glass bottle The extreme heat of the fire ignited by the A-bomb softened and deformed this glass bottle. After the bombs dropped: Hiroshima and Nagasaki 424495.bin 6th August 1945: An aerial view of the atomic bomb damage at Hiroshima. Getty Images After the bombs dropped: Hiroshima and Nagasaki 424497.bin The aftermath of the atom bomb dropped on Hiroshima, Japan, by the Americans at the end of World War II. The occupants of the burned-out bus were all killed. Getty Images After the bombs dropped: Hiroshima and Nagasaki 424499.bin Hiroshima after the atom bomb explosion. Getty Images After the bombs dropped: Hiroshima and Nagasaki 424500.bin This picture dated August 1945 in the Mariana Islands shows the US crew of the B-29 'Enola Gay' plane, including pilot Paul W. TIbbets (C), which dropped an atomic bomb on Hiroshima, Japan on 06 August 1945. Getty Images After the bombs dropped: Hiroshima and Nagasaki 424501.bin Colonel Paul Tibbets Jr, the pilot of the B-29 bomber 'Enola Gay', which dropped the atomic bomb on Hiroshima waves from the cockpit before takeoff. Getty Images After the bombs dropped: Hiroshima and Nagasaki 424502.bin A bombed out landscape in Hiroshima, Japan, following the explosion of the first atomic bomb. A few remaining buildings stand guard in a completely devastated area scattered with debris. Getty Images

“I think he is a person who can deliver the message of peace without inhibition,” said Negoro Fumiyo, a Christian from Osaka who waited for hours in the rain for the Pope’s mass, celebrated in Nagasaki’s baseball stadium before a crowd of some 35,000 – and the remains of a wooden statue of the Virgin Mary rescued from a cathedral destroyed in the 1945 atomic bomb.

The statue, which was remarkably well preserved despite the blast, was featured on the altar.

The Pope’s visit to Nagasaki also gave him the chance to honour Christian missionaries and martyrs centuries after St Francis Xavier first brought Christianity to the archipelago in 1549.

He laid a second wreath of flowers at the memorial of 26 Nagasaki martyrs, who were crucified in 1597 at the start of the two-century wave of anti-Christian persecution by Japanese rulers.

The example of the missionaries and martyrs, and the Hidden Christians who kept their faith alive underground for generations, helped inspire a young priest named Jorge Mario Bergoglio to be a missionary in Japan.

“May we never forget their heroic sacrifice!” the Pope said in remarks at the memorial.

Shingo Fukaura, from the Goto Islands off Nagasaki, where the “hidden Christians” survived during the time of persecution, travelled to Nagasaki bearing gifts he hoped to give the Pope at mass.

“I also brought this branch of the camelia tree, which has been on my island since the time when we, Christians, were hiding our faith,” he said.

“I am hoping he could give his blessing to this tree ... and I could take it back to the islands to make it a symbol of peace.”