VATICAN CITY — A prominent Nigerian nun blasted the culture of silence that has long kept clergy sexual abuse hidden in the Catholic Church, telling a Vatican summit Saturday that transparency and an admission of mistakes were needed to restore trust.

A German cardinal backed her up, telling the summit that church files about abusers had been destroyed, victims silenced and church procedures ignored, canceled or overridden – all in an attempt to keep the scandal under wraps.

Sister Veronica Openibo and German Cardinal Reinhard Marx delivered powerful speeches to nearly 190 church leaders gathered Saturday for the third day of Pope Francis’ four-day tutorial on preventing abuse and protecting children.

Openibo was one of only a handful of women invited to the meeting, and she used her time at the podium to shame the church leadership as a whole – men and women alike – for their silence in the face of such crimes.

“How could the clerical church have kept silent, covering these atrocities?” she asked. “We must acknowledge that our mediocrity, hypocrisy and complacency have brought us to this disgraceful and scandalous place we find ourselves as a church.”

Marx, for his part, called for a redefinition of the Vatican’s legal code of secrecy, known as the “pontifical secret,” and for the publication of statistics about the problem.

Marx said such action would be a first step toward restoring trust with the faithful and preventing conspiracy theories that the church was continuing to hide abuse.

“If we do not succeed, we either squander the chance to maintain a level of self-determination regarding information, or we expose ourselves to the suspicion of covering up,” he warned.

Francis summoned 190 bishops and leaders of religious orders to attend the conference in a bid to impress on the Catholic Church at large that sex abuse isn’t just a problem confined to a few countries, but the whole church.

The first two days of the meeting focused on the responsibility of church leaders in tending to their flocks, and how they must be held accountable when they fail to properly protect young people from predator priests. Saturday was dedicated to issues of transparency and breaking the code of silence that kept abuse hidden for so long.

Survivors who have gathered in Rome to protest decades of cover-up and demand accountability marched toward the Vatican shouting “Zero Tolerance.”

Among the marchers was Alberto Athie of Mexico, one of the original accusers of the pedophile founder of the Legion of Christ, the Rev. Marcial Maciel.

In her speech to the summit, Openibo recalled the Oscar-winning film “Spotlight,” based on the Boston Globe’s prize-winning expose of clergy abuse and cover-up that sparked the explosion of cases coming to light in the U.S. in 2002.

Openibo, the superior of the Society of the Holy Child Jesus religious order, told African and Asian church leaders they must no longer justify their silence about sexual violence by claiming that poverty and conflict are more serious issues for the church.

“This storm will not pass by,” she warned them.

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