Pope Francis has issued a letter to Catholics around the world condemning the "crime" of sexual abuse by priests and subsequent cover-ups.
Francis demanded accountability in response to new revelations in the United States of decades of misconduct by the Catholic Church.
The Pope begged forgiveness for the pain suffered by victims and said lay Catholics must be involved in any effort to root out abuse and cover-ups.
He wrote: "Let us beg forgiveness for our own sins and the sins of others. An awareness of sin helps us to acknowledge the errors, the crimes and the wounds caused in the past and allows us, in the present, to be more open and committed along a journey of renewed conversion."
He attacked the self-referential clerical culture that has been blamed for the abuse crisis, with church leaders more concerned for their reputation than the safety of children.
Francis wrote: "If, in the past, the response was one of omission, today we want solidarity, in the deepest and most challenging sense, to become our way of forging present and future history. "
The Pontiff added: "We showed no care for the little ones; we abandoned them."
The Vatican issued the letter on Monday, ahead of Francis' trip this weekend to Ireland which is expected to be dominated by the abuse crisis.
The full letter can be read here.