Pope Francis makes his first South American trip in two years Sunday, for an eight-day tour of Ecuador, Bolivia and Paraguay -- but not his native Argentina.
The 78-year-old Jesuit pontiff, the first pope from his "beloved South America," has said he wants to highlight the plight of the poor on his home continent.
He is due to land in Ecuador's capital Quito at 3:00 pm (2000 GMT) and will give a Holy Mass in eight languages early Monday.
Francis's last visit to South America was a triumphant trip to Brazil that culminated with some three million people gathering in Rio de Janeiro along Copacabana beach for a mass at the end of a Catholic youth festival.
The Catholic Church has about 1.2 billion followers globally, and Latin America represents the biggest portion of that population.
But the region has seen declining numbers as more people turn to Protestant churches.
"I want to bear witness to the joy of the Gospel and bring God's tenderness and care," the pope said before leaving for South America.
"Especially children in need, the elderly, the sick, the imprisoned, the poor, those who are victims of this throwaway culture."
The papal visit coincides with a time of political tension in Ecuador.
Embattled President Rafael Correa, an avowed admirer of Francis who describes himself as a "humanist Catholic of the left," has faced weeks of protests demanding his ouster over his policies, including an initiative to increase inheritance taxes.
"We are filled with joy at the coming of Pope Francis, the first Latin American pope," Correa said in his weekly address.
"How the Church is changing! What a strong message you are bringing."
Correa will meet with the pope late Monday.
- Outspoken advocate -
Since he was elected pope in March 2013, Francis has become an outspoken advocate for the poor and on social and environment issues.
Last month, he urged the world to act quickly to prevent "extraordinary" climate change from destroying the planet.
In his ninth trip abroad, the three countries the pope is visiting are predominantly Catholic and have long struggled with poverty and inequality, which especially afflict the indigenous population.
The visit is the second to Ecuador by a pope, with John Paul II coming in 1985.
Then, about 94 percent of the population was considered Catholic, compared to 80 percent today in the country of some 16 million inhabitants.
The decrease has come as evangelical churches have attracted huge numbers of followers, many of whom are indigenous people who have grown tired of a lack of attention from the Catholic hierarchy.
Francis is expected to make particular references to these communities.
The pope's visit will see him leave for La Paz, Bolivia on Wednesday.
He departs that country for Paraguay on Friday, before returning to Rome on July 12.