Pontiff hugs Mexico prisoners, warns businesses on slave labour

Pope Francis has on Thursday warned during a meeting with workers and business leaders in Ciudad Juarez that God would hold modern-day slavers accountable.

The city on Mexico's northern border with the U.S. is a major manufacturing and export centre as well as a flashpoint for immigration and organised crime.

"Poverty is the most favourable breeding ground for youth to fall into the spiral of drug trafficking and violence.

That spiral and its consequences were the focus of the visit to Juarez on the final day of the pope's five-day trip to Mexico.

Earlier in the day, Francis brought a message of hope to about 700 inmates at the Cereso 3 prison, encouraging them to look ahead and prepare themselves for a better life outside jail.

He also departed from his pre-planned speech to slam "the social hoax that believes that security and order can only be achieved by jailing people".

"Prisons are an indication of the kind of society we are.

"In many cases they are a sign of the silence and omissions which have led to a throwaway culture, a symptom of a culture that has stopped supporting life, of a society that has abandoned its children," he said.

Dire conditions and violence have long plagued Mexico's prisons. As a prison band played traditional Mexican songs and a tango for the Pope, Francis shook hands, embraced and kissed scores of inmates at the facility, which holds about 3,000 prisoners.

Later in the day, the pope was expected to hold the final and climactic event of his visit, a cross-border mass celebrated just 80 metres from the river separating the U.S. and Mexico.

The pope was expected to lay flowers at the border and pray in remembrance of migrants who have died on both sides.

Mexican officials said as many as 210,000 people are expected to gather for the mass on the Mexican side.

The officials said as many as 50,000 people would pack the Sun Bowl stadium in El Paso for a remote viewing of the mass.

They said since his arrival in Mexico Friday, Francis had criss-crossed the country to sharply criticise the political class, civil society and even the Catholic Church for their perceived inequality, indifference and injustice.

The pope has also drawn criticism for not holding an audience with families of victims of violence, including the 43 students who disappeared in southern Mexico a year and a half ago.

There will be a farewell ceremony for Pope Francis after the mass. Afterward, he is scheduled to depart Ciudad Juarez airport for Rome at 7:15 p.m.