Pope Francis reaches the halfway mark of his South American pilgrimage Thursday, celebrating his first Mass in Bolivia and meeting with workers' cooperatives and other grass-roots groups representing the poor whose causes have long been championed by history's first Latin American pope.

When Francis headlined the first such summit of grass-roots groups at the Vatican last October, he issued a remarkable, off-the-cuff monologue on the injustice of unemployment, the scandal of poverty and the obligation to care for the Earth.

"Terra, Techo, Trabajo," was his mantra then. "Land, Roof, Work."

"I talk about this some people think the pope is a communist," he told the gathering of miners, indigenous leaders and "cartoneros" who sift through garbage looking for recyclable goods. "They don't realize that love for the poor is at the center of the Gospel."

Francis arrived in Bolivia from Ecuador on Wednesday, embraced by President Evo Morales on the tarmac of La Paz where Francis praised Bolivia for taking "important steps" to include the poor and marginalized in the political and economic life of South America's poorest country.

Morales, Bolivia's first indigenous president, came to power championing Bolivia's 36 indigenous groups and enshrined their rights in the constitution. Under his leadership Bolivia's economy has boomed thanks to high prices for its natural gas and minerals.

But Morales has roiled the local Catholic Church by taking a series of anti-clerical initiatives, including a new constitution that made the overwhelmingly Catholic Bolivia a secular country. As soon as Morales took office in 2006, the Bible and cross were removed from the presidential palace and Andean religious rituals have now replaced Catholic rites at official state ceremonies.

In his speech, Francis noted the Catholic faith took "deep root" in Bolivia centuries ago "and has continued to shed its light upon society, contributing to the development of the nation and shaping its culture."

"The voice of the bishops, which must be prophetic, speaks to society in the name of the church, our mother, from her preferential, evangelical option for the poor," he said.

Morales, for his part, recalled how the Catholic Church in the past was on the side of the oppressors of Bolivia's people, three-quarters of whom are of indigenous origin. But Morales, an Aymara Indian known for his socialist stands, said things have changed with this pope and the Bolivian people are greeting Francis as someone who is "helping in the liberation of our people."

"He who betrays a poor person, betrays Pope Francis," Morales said.

Morales then offered Francis an unusual gift: a crucifix carved into a wooden hammer and sickle, the Communist symbol of the joining together of workers and peasants.

While Morales is known for his anti-capitalist bent, the ideologically charged gift actually had a very personal back story to it: A Jesuit priest killed by the Bolivian military regime in 1980, the Rev. Luis Espinal, had an identical crucifix.

Espinal, a follower of the left-wing liberation theology, was kidnapped and tortured by Bolivia's right-wing regime before his body was dumped on a highway in La Paz.

Moments after arriving Wednesday, Francis stopped his motorcade to pray by the assassination site, in a poignant reminder of his own experiences with Argentina's military dictatorship. The then Rev. Jorge Mario Bergoglio led the Jesuit order in Argentina in the 1970s when two fellow priests were kidnapped by the regime, which had joined like-minded governments in Bolivia and Paraguay to mount Operation Condor to wipe out and "disappear" leftist opponents.

"Remember one of our brothers, a victim of interests that didn't want him to fight for Bolivia's freedom," Francis said from the popemobile to a crowd gathered at the site Wednesday. "Father Espinal preached the Gospel, the Gospel that bothered them, and because of this they got rid of him."

Morales gave Francis another politically-charged gift: a copy of "The Book of the Sea," about the loss of Bolivia's access to the sea during the War of the Pacific with Chile in 1879-83. Bolivia has recently taken its bid to renegotiate access to the Pacific to the International Court of Justice, arguing that its poverty is due in part to being land-locked. Chile has argued the court has no jurisdiction since Bolivia's borders were defined by a 1904 treaty.

Francis referred to the border dispute in a speech to civil authorities in La Paz, calling for countries of the region to improve their diplomatic relations "in order to avoid conflicts between sister peoples and advance frank and open dialogue about their problems."

"I'm thinking about the sea, here," he said. "Dialogue is indispensable."

"Instead of raising walls, we need to be building bridges," he said.

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