Pope Francis launched a scathing attack on organized crime during a trip to the heartland of a feared syndicate on Sunday, declaring all mafia members "excommunicated" from the Catholic Church.

The mafia "is the adoration of evil and contempt for common good. This evil must be beaten, expelled," he told worshippers near the hometown of a toddler killed in a clan war earlier this year.

"Those who in their lives follow this path of evil, as mafiosi do, are not in communion with God. They are excommunicated," he told the congregation.

It was the first time a pope had used the word excommunication - a total cutoff from the Church - in direct reference to members of organized crime.

People who are excommunicated are expelled from the Church, unless they repent, and are considered to be condemned to Hell in the afterlife.

The 77-year-old pontiff was speaking at the end of a trip to the territory controlled by the powerful 'Ndrangheta mafia, where he comforted relatives of "Coco" Campolongo, a 3-year-old who was shot dead in January in an apparent mob hit over money.

"It must never again happen that a child suffers in this way," the pope said as he met Coco's father and grandmothers, according to a Vatican spokesman.

Francis visited the Calabria region despite fears he might provoke the local underworld.

"I pray for him continuously. Do not despair," Francis said during a visit to Castrovillari prison, where several members of Coco's family are serving time for drug-related crimes.

The pope's trip to Italy's  second-poorest aims to remember child victims and highlight the problems the young have in escaping the pervasive grip of the wealthy 'Ndrangheta.

According to Save the Children Italy, more than a third of all families in the impoverished south live in communities under the control of clans

Many of the inmates the pope met at Castrovillari were serving time for mafia-related crimes.