Pope Francis has challenged the Mexican government to provide "true justice" to citizens affected by the brutal drug violence epidemic that has devoured society "like a metastasis". The Pope also asked leaders in the world's second-most populous Catholic nation to do their "particular duty" to tackle corruption and violence.

The Argentinian-national was talking on the first day of a five-day visit to Mexico after he visited Cuba, where he joined Russian Orthodox Patriarch Kirill to call for Christian unity during landmark talks. He is due to head off to Brazil, Paraguay and Chile afterwards.

In Mexico he plans on meeting indigenous communities in impoverished Chiapas near the Guatemalan border, speak with young people in Morelia, the capital of the violence-ridden Michoacan state, and visit a prison in the infamous Ciudad Juarez – dubbed Mexico's most violent city.

The Pope spoke before he prayed with thousands at the Virgin of Guadalupe and celebrated mass at the vast Basilica of our Lady Of Guadalupe. Here the crowd held their breath as the unsteady 79-year-old lost his balance and almost tumbled backwards whilst placing flowers.

Corruption is endemic in Mexico – even President Enrique Pena Nieto, his wife and finance minister have been dragged into conflict of interest scandals involving homes purchased from government contractors.

An estimated 100,000 people have been killed in drug violence over the last decade with traffickers slaughtering police, indigenous communities, and each other. "Experience teaches us that each time we seek the path of privilege or benefits for a few to the detriment of the good of all, sooner or later the life of society becomes a fertile soil for corruption, the drug trade, the exclusion of different cultures, violence and also human trafficking, kidnapping and death," the Pope said in a speech to Pena Nieto, government ministers and foreign diplomats according to Reuters.

He also addressed migrants around the world, something he has done repeatedly since he took over from Joseph Ratzinger. He said: "Brothers, may your hearts be capable of following these men and women and reaching them beyond the borders."