Pope Francis has urged migrants to hang on to hope and treasure their own cultures and values.
Addressing as many as 6000 migrants gathered in St Peter's Square for his regular Angelus prayer, the Pope said: "Dear migrants and refugees, each one of you carries within yourself a story, a culture, of precious value, and often unfortunately experiences of misery, oppression and fear. Alas, many of you have experienced misery, oppression and fear."
He said he viewed with great affection the ethnic communities in Vatican City and those who help and welcome the migrants.
Speaking on the World Day of Migrants and Refugees, and a day marked in Rome as a jubilee for migrants as part of his Jubilee Year of Mercy, he said the presence of so many migrants at St Peter's was a sign of hope in God. He said the migrants should not let themselves be robbed of hope and the joy of living, which derive from the experience of divine mercy.
Of 600,000 migrants in Italy, 500,000 are in Rome.
After the Angelus, the migrants attended a Mass inside St Peter's Basilica celebrated by Cardinal Antonio Maria Vegliò, President of the Pontifical Council for the Pastoral Care of Migrants and Itinerant Peoples.
The Pope offered special thanks to inmates at the Opera maximum security prison in Milan for donating the hosts used for the Mass.
He also prayed for the victims of the recent terror attacks in Indonesia and Burkina Faso.