Pope Francis has warned Latin America against legalizing drugs, arguing in sharply-worded and highly political remarks that liberal policies under consideration in his home region will not reduce the problem.
The Argentine-born pontiff delved into the hot topic on Wednesday after celebrating the first public mass of his week-long visit to Brazil, in which he has sought to deliver a message of hope to the poor and vulnerable.
He drew a line against drugs as he met crack addicts and inaugurated a rehabilitation ward at a Rio de Janeiro hospital run by Franciscan monks.
"The scourge of drug trafficking, which favors violence and sows the seeds of suffering and death, requires of society as a whole an act of courage," Francis said as rain fell on the Saint Francis hospital.
"A reduction in the spread and influence of drug addiction will not be achieved by a liberalization of drug use, as is currently being proposed in various parts of Latin America," he said on the third day of his trip
Hours earlier, the 76-year-old pope, in Brazil for a Catholic youth festival, urged Catholics to reject "ephemeral idols" such as money, power and success as he led mass at the country's most revered shrine.
Drug violence has killed more than 70,000 people in Mexico alone since 2006, while narcotrafficking continues unabated across Latin America, fueling calls for a rethink of the US-backed "war on drugs".
Guatemala's president has called for legalization, a vision shared by ex-presidents in Brazil, Mexico and Colombia but opposed by the United States and Mexican governments.
Uruguayan President Jose Mujica has proposed legalizing marijuana in his country.
But the pope said society must fight the underlying problems of drug use by "promoting greater justice, educating young people in the values that build up life in society, accompanying those in difficulty and giving them hope for the future."
Latin America's first pope visited the hospital after flying back from a mass at the Shrine of Our Lady Aparecida in neighboring Sao Paulo state, where more than 200,000 people braved the cold rain to greet him.
After entering the basilica, the visibly moved pontiff held a statue of the dark-skinned Virgin of Aparecida, Brazil's patroness whom Francis himself reveres.
"It is true that nowadays, to some extent, everyone, including our young people, feels attracted by the many idols which take the place of God and appear to offer hope: money, success, power, pleasure," he said.
"Often a growing sense of loneliness and emptiness in the hearts of many people leads them to seek satisfaction in these ephemeral idols," the homily added.
The Catholic leader is seeking to re-energize the faithful during his first overseas trip since his election earlier this year.
It was in Aparecida in 2007 that the pope, then known as cardinal Jorge Mario Bergoglio, led a bishops' panel that drafted a document with a strong social and political appeal for the poor in Latin America.
The region is home to 40 percent of the world's 1.2 billion Catholics, but Brazil has seen its flock dwindle while Evangelicals gain ground against the background of pedophilia and financial scandals circling the Vatican.
An estimated 15,000 people packed the basilica for Wednesday's mass while another 200,000 gathered outside, with 5,000 police and soldiers providing security.
Last Sunday, authorities found and destroyed a homemade explosive in a parking lot bathroom, but the Vatican said it was no cause for concern.
After the mass, the pope stepped out to bless the crowd and announced he would return in 2017 on the 300th anniversary of the statue's discovery by three local fishermen.
"We want Francis's example to bring renewal to the Church, which sorely needs it," said 47-year-old Jose Antonio Rocha, who stood for hours outside to see the visitor pass by in a Popemobile.
The pope's smooth outing to Aparecida follows a tumultuous start to his trip. Crowds swarmed his car and managed to touch him when he arrived in Rio on Monday. Later that night, police dispersed anti-government protesters with tear gas after the pope met Brazilian President Dilma Rousseff.
Then, on Tuesday, Rio's subway broke down for two hours, causing chaos.
Rio Mayor Eduardo Paes apologized and said steps were being taken to avoid a repeat of such "deplorable incidents."
On Thursday, the pope, a football fan, will receive the keys of the city, bless the Olympic flag ahead of the 2016 summer Games and huddle with sports celebrities, possibly including the legendary Pele.
Next comes a tour of the Varginha shantytown, an impoverished community of 1,000 people and an evening address to hundreds of thousands of young Catholics on Copacabana beach.