SAO PAULO, Brazil — Pope Benedict XVI lamented the deep divide between rich and poor in Latin America but told priests to steer clear of politics as they work to reverse Roman Catholicism’s waning influence in the region.

Wrapping up five-day visit to Brazil, the 80-year-old pontiff denounced Marxism in an hour-long speech Sunday opening a 19-day conference of Latin American bishops in the shrine city of Aparecida.

“The Marxist system, where it found its way into government, not only left a sad heritage of economic and ecological destruction, but also a painful destruction of the human spirit,” the pope said.

He also warned of unfettered capitalism and globalization. Before boarding a plane for Rome later Sunday, he said the two could give “rise to a worrying degradation of personal dignity through drugs, alcohol and deceptive illusions of happiness.”

Marxism still influences some grassroots Catholic activists in Latin America, remnants of the liberation theology movement Benedict worked to crush when he was cardinal. Liberation theology holds that the Christian faith should be reinterpreted specifically to deliver oppressed people from injustice.

Benedict defended the church’s often bloody campaign to Christianize indigenous people, saying Latin American Indians had been “silently longing” to become Christians when Spanish and Portuguese conquerors took over their native lands centuries ago.

“In effect, the proclamation of Jesus and of his Gospel did not at any point involve an alienation of the pre-Columbus cultures, nor was it the imposition of a foreign culture,” he told the bishops.

Throughout his first papal visit to the region, Benedict emphasized Catholic moral values as the answer to Latin America’s social and economic problems.

Returning to that theme Sunday, he warned that legalized contraception and abortion in Latin America threaten “the future of the peoples” and said the historical Catholic identity of the region is under assault.

While Brazil is the most populous Roman Catholic country, home to more than 120 million of the world’s 1.1 billion Catholics, the census shows that people calling themselves Catholics fell to 74 percent in 2000 from 89 percent in 1980.

Those calling themselves evangelical Protestants rose to 15 percent from 7 percent.

The pope did not name any countries in his criticism of capitalism and Marxism, but Latin America has become deeply divided in recent years amid a sharp tilt to the left — with the election of leftist leaders in Bolivia, Ecuador and Nicaragua and the re-election of President Hugo Chavez in Venezuela. Center-left leaders govern in Brazil, Argentina and Uruguay.

Religious experts said Benedict failed to address key challenges to the church in Latin America, including a severe shortage of priests or a specific strategy for how parishes should try win back Catholics who have turned into born-again Protestants or simply stopped going to church.