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Ricardo Mazalan, Associated Press
Argentina's fans hold a banner with the images of Argentina's Lionel Messi, right, Pope Francis, center, and Argentina's soccer legend Diego Maradona, during the final Copa America soccer match between Argentina and Chile at the National Stadium in Santiago, Chile, Saturday, July 4, 2015.

QUITO, Ecuador — Latin America's first pope returned to Spanish-speaking South America on Sunday for the first time, beginning a nine-day tour that will take him to three of the continent's poorest countries.

Children in traditional dress greeted Pope Francis at Quito's Mariscal Sucre airport, the wind blowing off his skullcap and whipping his white cassock as he descended from the plane following a 13-hour flight from Rome. He personally greeted and kissed several indigenous youths waiting for him on the side of the red carpet.

The "pope of the poor" will highlight in his visit to Ecuador, Bolivia and Paraguay his priorities of protecting the marginalized and the planet from injustice and exploitation.

In a speech in front of President Rafael Correa, he immediately signaled key themes: the need to care for society's most marginal, ensuring socially responsible economic development and, turning to Ecuador specifically, defending "the singular beauty of your country."

"From the peak of Chimborazo to the Pacific coast, from the Amazon rainforest to the Galapagos Islands, may you never lose the ability to thank God for what he has done and is doing for you," he said, praising Ecuador's "singular beauty."

The Pacific nation of 15 million is home to more than 20,000 plant species as well as the Galapagos Islands, which inspired Charles Darwin's theory of evolution in 1535.

Thousands lined the motorcade route that would take Francis him to the Vatican ambassador's residence, many hopeful the pope will have a calming effect.

Travel agency worker Veronica Valdeon called the Argentine pontiff "a light in the darkness. "We are living difficult moments in our country," she said, "and Francis brings a bit of joy."

Francis is to preside over two big open-air Masses in his three days in Ecuador — one in the steaming Pacific port of Guayaquil on Monday, the other Tuesday in the capital on the site of the city's former airport.

Francis' stops later include a violent Bolivian prison, a flood-prone Paraguayan shantytown and a meeting with grass-roots groups in Bolivia, the sort of people he ministered to in the slums of Buenos Aires as archbishop.

Crowds are expected to be huge. While the countries themselves are small, they are fervently Catholic: 79 percent of the population is Catholic in Ecuador, 77 percent in Bolivia and 89 percent in Paraguay, according to the Pew Research Center.

Beyond the major public Masses in each country, Vatican organizers have scheduled plenty of time for the pope to meander through the throngs expected to line his motorcade route.

Associated Press writers Gonzalo Solano and Maria Jose Sanchez contributed to this report.