TOKYO -- Pope Francis denounced the "evil" of nuclear weapons on Saturday as he began a three-day visit to Japan and fulfilled a dream to be a missionary in a land with a rich but bloody Christian past.

The pope's plane landed in the rain in Tokyo, where he received a small welcome at the airport before heading to the Vatican residence to meet with Japanese bishops. Streets near the residence were lined with smiling well-wishers holding umbrellas. One group held a banner that read: "Gracias! We love you."

After a packed three days in Thailand, Francis has an even busier schedule in Japan, starting off with flights Sunday to Nagasaki and Hiroshima to appeal for total nuclear disarmament, and a meeting Monday with victims of the 2011 Fukushima nuclear disaster.

Those meetings come before he even meets with Emperor Naruhito and Prime Minister Shinzo Abe in a sign of his priorities for the trip.

Francis told the bishops upon arrival that he wanted to pay tribute to the victims of the atomic bombings and meet with survivors, "those who still bear the wounds of this tragic episode in human history."

"Evil has no preferences; it does not care about people's background or identity," Francis said. "It simply bursts in with its destructive force."

Francis has gone further than any other pope by saying that not only the use but the mere possession of nuclear weapons is "to be condemned."

It's a message he's expected to repeat Sunday, and it's one that has been welcomed by Japanese old enough to remember the bombings.

"I hope he will deliver the message of true peace to Japan and to the world," said Ryohei Sakamoto, 71, a Catholic who was waiting for Francis outside the nunciature Saturday afternoon. "And I hope the world will listen to him and his message. That's what I wish he could do on this visit."

Francis told the bishops how as a young Jesuit in Argentina, he had longed to be a missionary in Japan, following in the footsteps of St. Francis Xavier, the Jesuit who first brought Christianity to the archipelago in 1549.

While health reasons prevented Francis from realizing that dream, he said he nevertheless nurtured a continued affection for Japan and was inspired by the Christians who endured more than two centuries of persecution starting in the 16th century.

"Such self-sacrifice for the sake of keeping the faith alive amid persecution helped the small Christian community to develop, grow strong and bear fruit," Francis told the bishops.

One of the highlights of the trip will be Francis' prayer Sunday at the memorial of the 26 Nagasaki Martyrs, who were crucified in 1597 at the start of the wave of anti-Christian bloodshed by Japanese rulers.

Francis will also greet descendants of the "Hidden Christians," who persevered in their faith for generations despite the threat of death and the absence of priests.

Francis' other key aim in coming to Japan is to tend to today's tiny Catholic flock, which has grown exponentially more diverse in recent years due to an influx of foreign workers. Today, these temporary workers make up more than half of Japan's Catholic population of 440,000, according to the Archdiocese of Tokyo's international centre.

Overall, Catholics account for less than 0.5% of Japan's 127 million people, most of them loosely affiliated with Buddhism or Shinto, or both.

Japan had long kept its door closed to immigrants, but the country last year adopted a new policy to open up unskilled jobs to temporary foreign workers, a major revision to the country's policy to deal with its rapidly aging and declining population.

Many of the newcomers hail from the Philippines, Vietnam and Brazil and are Catholic, rejuvenating local churches that now offer Masses in English, Tagalog, Portuguese, Spanish and Vietnamese.

Francis has made welcoming migrants a hallmark of his papacy, and he told his bishops that their ministry to foreign workers was a precious demonstration of their commitment to spreading the faith.

He urged them also to look out for young Japanese, who he said were increasingly prone to "loneliness, despair and isolation."

"The increase in the rates of suicide in your cities, as well as bullying and various kinds of neediness, are creating new forms of alienation and spiritual disorientation," he warned. He urged them to encourage a shift from a "culture of efficiency, performance and success" to one of "generous and selfless love, capable of offering to everyone, and not only to those who have `made it,' the possibility of a happy and successful life."

Suicides in Japan have been on the decline for nearly a decade to just over 20,000 last year, but the number is on the rise among teenagers and the elderly.

Francis himself was offering some joy to the few people invited to welcome him at the Vatican residence Saturday night.

"I am so looking forward to seeing him and I cannot wait!" gushed Michiko Haramoto, a 71-year-old Catholic who travelled from southern Fukuoka, on Kyushu island, to greet the pope. She said she would be on the first flight to Nagasaki on Sunday to attend Francis' Mass.

"I don't know how and whether it's possible. But if I get to talk to him directly at all, it will be so wonderful and I will surely tell him how grateful we all are here upon receiving him," she said.

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Associated Press videojournalist Kaori Hitomi contributed to this report.