pope francis
© Craig Ruttle / Reuters
Pope Francis has called for "zero tolerance" towards sex crimes against children and condemned as "a sin that shames" both perpetrators of such offences among the clergy as well as those who cover up such atrocities.

The head of the Catholic Church addressed bishops across the globe in a letter on December 28, but it was released by the Vatican press service only on Monday. The letter focused on scourge of child sexual abuse within the Church.

"Christmas is ... accompanied, whether we like it or not, by tears. The Evangelists did not disguise reality to make it more credible or attractive. They did not indulge in words that were comforting but unrelated to reality," the Pope wrote.

Since his election in 2013, Pope Francis has undertaken several steps to battle shameful practices within the Church and to protect children. The problem still exists however, as "we hear this heart-rending cry of pain, which we neither desire nor are able to ignore or to silence."

"Can we truly experience Christian joy if we turn our backs on these realities? Can Christian joy even exist if we ignore the cry of our brothers and sisters, the cry of the children?" the Pontiff asks.

Critics, however, still criticize the Pope for his lack of action against child abusers within the Church, specifically against bishops, who ignored and covered up child abuse practices. The Pope condemned it as a sin that shames the Church.

"We hear these children and their cries of pain; we also hear the cry of the Church our Mother, who weeps not only for the pain caused to her youngest sons and daughters, but also because she recognizes the sins of some of her members: the sufferings, the experiences and the pain of minors who were abused sexually by priests. It is a sin that shames us," the Pope's letter reads.

"Persons responsible for the protection of those children destroyed their dignity. We regret this deeply and we beg forgiveness. We join in the pain of the victims and weep for this sin... The Church also weeps bitterly over this sin of her sons and she asks forgiveness."

Pope Francis highlighted the alarming world-wide scale of child abuse, which he said manifests itself in different forms, apart from sex, and urged the bishops to eradicate the practice.

"There are at present 75 million children who, due to prolonged situations of emergency and crisis, have had to interrupt their education. In 2015, 68% of all persons who were victims of sexual exploitation were children. At the same time, a third of all children who have to live outside their homelands do so because forcibly displaced," Pope Francis said in the letter.

The Pope then expanded and highlighted the plight of children around the globe. "We live in a world where almost half of the children who die under the age of five do so because of malnutrition. It is estimated that in 2016 there were 150 million child labourers, many of whom live in conditions of slavery. According to the most recent report presented by UNICEF, unless the world situation changes, in 2030 there will be 167 million children living in extreme poverty, 69 million children under the age of five will die between 2016 and 2030, and 16 million children will not receive basic schooling," he said.

Apart from speaking out and mourning for the victims, the Pope promised to undertake concrete measures and establish a "zero tolerance" policy towards child abusers. This policy is aimed both at priests molesting children, as well as those who committed "the sin of covering up and denial, the sin of the abuse of power," in reference to high ranking clerics and bishops.

In 2015, Pope Francis ordered the trial and defrocking of a Polish archbishop, who allegedly paid for underage sex in the Dominican Republic.

The Pope has met victims of sexual crimes victims on numerous occasions during his visits abroad and at the Vatican. He has also established a Vatican commission to help local churches prevent sexual abuse. Several members of the commission, however, some of whom were sex abuse victims themselves, have complained about the inefficiency of the commission.

In addition, the Pope has approved the creation of a special Vatican tribunal to judge bishops, who cover up sexual abuse. However, the initiative has had little success so far.

"Let us not allow them to be robbed of [Christian] joy. Let us not allow ourselves to be robbed of joy, but guard it and nourish its growth," the Pope concluded his letter.