The Pope was speaking during the signing ceremony of an ecumenical agreement between leaders belonging to different religions, who met with the aim of eradicating the scourge of slavery worldwide by 2020.
The event was attended by representatives of a number of the world’s religions.
Among those taking part were Hindu guru Mata Amritanandamayi, Argentinian rabbi Abraham Skorka, rabbi David Rosen of the American Jewish Committee, French Orthodox metropolitan bishop Emmanuel, Iraqi Grand Ayatollah Mohammad Taqi al-Modarresi, Archbishop of Canterbury Justin Welby and Buddhist representatives, among others.
The Pope said that modern slavery, despite all efforts, remains a terrible scourge and is still practiced worldwide on a large scale, including sexual tourism.
He said modern slavery is found in streets, factories, houses, cities and villages, as well as in rich and poor nations.
Its victims are from all walks of life, but those who suffer most are the poor and the most vulnerable, the Pope added.
Every human being is a free person and all people are equal and possess the right to live in dignity and freedom, he noted.
The pontiff declared that by signing such a historic initiative, different religions would work together to eliminate modern slavery in all its forms, including sexual and psychological ones, which subject daily tens of millions of people to humiliation and dehumanisation.
He urged all nations, leaders, governments, businesses and all people with good intentions to join this struggle.
He also called for help and support for the elderly, refugees and young people forced into the sex trade, and for the fight against the forced prostitution of women and children.