VATICAN CITY (AP) — Pope Francis is urging the world to show a greater commitment to fighting human trafficking, which he called “a form of modern slavery.”

The pope made the appeal during his traditional Sunday (July 30)  prayer on the United Nations’ World Day Against Trafficking.

“Every year, thousands of men, women and children are innocent victims of labor exploitation, and sex and organ trafficking,” Francis said. He added that it has become something considered normal: “This is ugly. It is cruel. It is criminal.”

He called on the world to renew its commitment to battling “this abhorrent plague, a form of modern slavery,” and to pray that traffickers “change their hearts.”

The International Labor Organization estimates 21 million people are victims globally of forced labor, including victims of human trafficking for labor and sexual exploitation.