Pope Francis
Pope Francis reacts to a comment during his weekly audience at St Peter's at the Vatican.Reuters/Alessandro Bianchi

Pope Francis has lashed out against a horrifying crime of paedophilia, but failed to mention the Catholic church's own struggles with the problem . The pontiff had harsh words for a heinous crime that police said ended with an alleged attacker pushing his six-year-old victim to her death from the balcony of an eight-story building.

"This is a tragedy. We should not tolerate the abuse of minors," the pope said, departing from prepared remarks at his weekly Sunday message and blessing to tens of thousands of people in St Peter's Square in the Vatican.

"We must protect minors and severely punish abusers," he said. Though the church has been rocked by abuse scandals, Francis did not mention them, though he has in the past.

Details of the 2014 death of Fortuna Loffredo, the little girl from Naples the Pope spoke of, have only recently come to light. Police re-opened the case and charged a neighbor who they claimed has raped Fortuna, then threw her to her death so she could not testify against him, reports the Irish Times.

The 44-year-old man was already in a Roman prison on charges he molested other children, including his own three-year-old daughter, reports ANSA. He has denied all the charges.

Italian president Sergio Mattarella called for an "ample, rapid and severe" judicial process on the case, which has dominated newspapers for days. Thousands of adults in the Catholic Church around the world have come forward to accuse priests of molesting them as children and accused leaders of covering up the abuse.

Tens of millions of dollars have been paid by the church to compensate victims. The pope has vowed "zero tolerance" for abusers in the church, but victims groups say he is not doing enough, and are calling on him to hold bishops accountable for covering up abuse or not preventing it.

A commission Francis established to advise him on how to deal with the problem has been roiled by debate. Earlier in 2016 prominent British member Peter Saunders stepped down in protest.