"Priority must not be given to any other kind of concern, whatever its nature, such as the desire to avoid scandal, since there is absolutely no place in ministry for those who abuse minors," he said in a written letter.

The letter, dated Feb. 2, the feast of the Presentation of the Lord, was sent to the presidents of national bishops' conferences worldwide and the superiors of religious orders. The Vatican released a copy of the letter Feb. 5, feast of St. Agatha, an early martyr who was abused and assaulted as a young woman.

In his letter the Pope said, "Families need to know that the church is making every effort to protect their children. They should also know that they have every right to turn to the church with full confidence, for it is a safe and secure home."

With protecting minors as a top priority, the Pope said he wants to encourage and promote the church's commitment to protection and care "at every level -- episcopal conferences, dioceses, institutes of consecrated life and societies of apostolic life -- to take whatever steps are necessary to ensure the protection of minors and vulnerable adults and to respond to their needs with fairness and mercy."

He reminded church leaders they were expected to implement fully the provisions in the 2011 circular letter from the Congregation for the Doctrine of the Faith requiring every bishops' conference in the world to develop guidelines on handling allegations of abuse. The guidelines, to be prepared by each bishops' conference and then reviewed by the doctrinal congregation, are to provide diocesan bishops and major superiors with clear and coordinated procedures for protecting children, assisting victims of abuse, dealing with accused priests, training clergy and cooperating with civil authorities.

Pope Francis wrote that "it is likewise important that episcopal conferences establish a practical means for periodically reviewing their norms and verifying that they are being observed."

The United States bishops' conference, for example, appoints an all-lay board that monitors and annually reviews how dioceses have complied with its national "Charter for the Protection of Children and Young People."

The Pope underlined that it is "the responsibility of diocesan bishops and major superiors to ascertain that the safety of minors and vulnerable adults is assured in parishes and other church institutions."

The church also has the "duty to express the compassion of Jesus toward those who have suffered abuse and toward their families," which is why dioceses and religious orders should set up pastoral care programs, "which include provisions for psychological assistance and spiritual care."

Bishops and heads of religious communities "should be available to meet with victims and their loved ones; such meetings are valuable opportunities for listening to those who have greatly suffered and for asking their forgiveness," he wrote.

He said that when he met individually with six abuse survivors in 2014 he was "deeply moved by their witness to the depth of their sufferings and the strength of their faith."

Meeting those men and women, he said, "reaffirmed my conviction that everything possible must be done to rid the church of the scourge of the sexual abuse of minors and open the pathways of reconciliation and healing for those who were abused."

In establishing the Pontifical Commission for the Protection of Minors in December 2013, he said, he wanted a body that would propose ways for the church to improve its norms and procedures for protecting children and vulnerable adults.

This commission, led by U.S. Cardinal Sean P. O'Malley of Boston and made up of survivors and lay experts in the field, is meant to be "a new, important and effective means for helping me to encourage and advance the commitment of the church at every level" in taking concrete steps to ensure greater abuse protection and care, he said.

The commission was scheduled to meet at the Vatican Feb. 6-8; it would be the commission's first meeting since Pope Francis added new members in late January.

In his letter, Pope Francis asked for the "close and complete cooperation" of the world's bishops' conferences and religious orders with the commission, whose duties include assisting church leaders in "an exchange of best practices and through programs of education, training and developing adequate responses to sex abuse."

The Pope asked for prayers that the church "carry out, generously and thoroughly, our duty to humbly acknowledge and repair past injustices and to remain ever faithful in the work of protecting those closest to the heart of Jesus."