Tens of thousands of cheering faithful greeted Pope Francis Monday on his arrival in Brazil, mobbing a motorcade carrying the pontiff into central Rio de Janeiro at the start of a weeklong visit.
Video showed security officers struggling at several points to push back the joyous crowds, while the pope rolled down the window of his car to touch those who reached inside. One woman handed the 76-year-old pope an infant, whom he kissed before handing back.
Brazilian President Dilma Rousseff and a host of dignitaries met the Argentine-born Francis -- the former Cardinal Jorge Bergoglio -- as he stepped off a commercial airliner to begin his visit.
Later, anti-government protesters clashed with police outside the palace holding the official papal welcoming ceremony. Reports from the scene said crowd anger appeared directed at Brazilian leaders, not at the pontiff.
Separately, police in the neighboring state of Sao Paulo, where the pope will visit a Catholic shrine later this week, said they safely detonated a small, homemade explosive device found in a parking garage at the shrine.
Police described the explosive as low-powered and said it was not clear whether it was related to the papal visit.
The pope's heavily policed visit comes at a time of social upheaval that began with protests in June against a bus fare increase in Sao Paulo. Those demonstrations quickly grew into massive street protests against government expenditures for hosting football's 2014 Word Cup, and then spread to include protests against official corruption.
The Rio visit and the return to Francis' home continent is set to coincide with Thursday's international celebration of World Youth Day. More than 1 million young Catholics are expected to participate in the events.
The pontiff's schedule also includes a meeting with young inmates at a Rio prison and a visit to shantytowns largely cleared of drug traffickers earlier this year. He also will inaugurate a Rio hospital wing for the treatment of drug addicts and will pray at a shrine to Our Lady of Aparecida, the patron saint of Brazil.
Aboard his flight from Rome, the pope told journalists he is worried that the world, with high jobless rates for young people, is running "the risk of having a generation without work," even though he said work confers dignity.
He also criticized the "culture of rejection" of the elderly, saying they should not be "thrown away" by cultures that concentrate on everything new.