Pope Francis threw himself into the most contentious of issues roiling Mexico during his first full day here, calling on President Enrique Peña Nieto and his government to protect citizens and bring justice to a country racked by violence and corruption.

Kicking off the first leg of his six-day tour of the Spanish-speaking world’s largest Catholic country, the pontiff offered an unvarnished assessment of Mexico’s troubles and the need for honesty and faith to overcome them. His first speech, addressing Peña Nieto and other top Mexican officials, took place inside the National Palace, as tens of thousands of people filled the Zocalo plaza outside and listened to remarks broadcast on jumbo screens.

“Each time we seek the path of privileges or benefits for a few, to the detriment of the good of all, the life of society becomes a fertile soil for corruption,” the pope said, “drug trade, exclusion of different cultures, violence and also human trafficking, kidnapping and death.”

Francis said Mexico’s political class had the duty to give its people access to “an adequate home, dignified work, food, real justice, effective security, and a peaceful and sane environment.”

One of the world’s mega-cities ground to a halt to greet Francis, with roads barricaded miles from his events and police and soldiers out in force to maintain security amid the hundreds of thousands who came to get a glimpse of the popular pontiff. Students were off from classes Friday and many businesses closed as residents lined the streets waiting for a glimpse of the popemobile as it wended through the streets.

Francis plans to visit the extremes of Mexico, from the poor, heavily indigenous southern border state of Chiapas, which has become a way station for thousands of Central American migrants, to the northern border town of Ciudad Juarez, which is recovering from its dark drug-war years.

Those backdrops, plus a planned stop in the volatile western state of Michoacan, give Francis plenty of opportunity, if he chooses, to highlight Mexico’s recurrent failings with violence, immigration, poverty and government corruption. Plus, with anti-immigrant sentiment surging in the U.S. presidential race, the pope could enter that fray by his example of showing compassion for the downtrodden. With all the problems in Mexico, “we need the pope to show us the light,” said Leticia Gutierrez Valderrama, a nun who directs an organization that works with migrants.

After the pope spoke in the National Palace, he moved across the plaza to the city’s Metropolitan Cathedral, which was built beginning in the 16th century on top of an Aztec temple. He addressed Mexican bishops, speaking in his hypnotic near-whisper, in his Argentine-accented Spanish.

“I beg you, please don’t underestimate the ethical and civic challenge drug trafficking poses to youth and the entire Mexican society, including the church,” Francis said.

The crowd in the Zocalo, which had been sitting quietly in the bleachers listening to his words, erupted in cheers when the pope condemned drug trafficking. Mexicans seemed to be yearning for Francis to strike a serious tone, to recognize the gravity of their problems and to call their government to account.

“There is so much injustice in Mexico,” Ruben Sandoval said as he motioned to the National Palace. The 44-year-old accountant had come to the Zocalo to hear the pope’s speech, and to welcome “the representative of God on this earth” to Mexico. “There’s a lack of work, a lack of education, a lack of opportunity. And I hope the government bears that in mind.”

On Friday evening, Francis stepped down from his Alitalia airliner and was greeted by a field of waving lights, as cheering crowds roared their approval from bleachers erected on the flight apron of the Mexico City airport.

Francis was met by a beaming Peña Nieto and his wife, Angelica Rivera, who walked the pope down a red carpet and introduced him to a variety of Mexican officials. The scene was jubilant, with mariachis wearing sombreros and dancers performing lasso rope tricks in front of the smiling pope. At one point, Francis tried on a sombrero from one of the musicians.

“Francis, friend, you are welcome here,” the crowd chanted.

Many expect the pontiff’s trip will be used to address the social upheaval here and in Central America, as thousands flee gang violence in search of safety and jobs in the United States. Francis was expected to meet, or have in attendance, relatives of the 43 students at a teachers college who disappeared in 2014, a scandal that has highlighted the links between government and drug traffickers and the inability of Mexican investigators to arrive at the truth.

“Those who thought the pope was going to be sweet and diplomatic, that it was going to be a rose-colored visit, were wrong,” said Bernardo Barranco, a sociologist who studies religion. “That pope has come in strong. Very strong.”

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