Pope Francis on Tuesday urged countries to welcome and respect migrants and refugees and not treat them as "pawns on the chessboard of humanity."

Francis's comments come at a time when immigration has become a divisive issue in Europe and Australia and one day after a report showed an increase in illegal immigration to the United States.

The pontiff, who has made the defense of the poor and vulnerable a cornerstone of his papacy, said that there should be a change in attitude on the part of host countries.

"They are children, women and men who leave or who are forced to leave their homes for various reasons, who share a legitimate desire for knowing and having, but above all for being more," Francis said.

The pope's own ancestors left Italy for Argentina in the early 20th century and lived through the Great Depression.

Francis also repeated his condemnation of "slave labor" and trafficking, expanding his criticism of "throwaway culture." He has often used the term to denounce a modern society where people who are not productive, such as the elderly, are neglected and cast off as if they were useless.