Rome (CNN) Pope Francis began an unprecedented summit in Rome to confront the Catholic Church's clergy abuse scandal by saying that Catholics are not looking for simple condemnation, but concrete actions.

"In the face of this scourge of sexual abuse perpetrated by men of the church to the detriment of minors, I thought I would summon you," the Pope told the nearly 200 Catholic leaders gathered in Vatican City, "so that all together we may lend an ear and listen to the Holy Spirit ... and to the cry of the small ones who are asking for justice."

"The holy people of God are looking at us and expect from us not simple condemnations," Francis continued in his opening address, "but concrete and effective measures to put in place. We need to be concrete."

For the first time in Catholic history, the almost 200 global church leaders are gathering at the Vatican to address the crisis. The four-day summit, convened by the Pope last September, will include two speeches by Francis, talks outlining best practices, small group discussions among bishops and a penitential ceremony involving abuse survivors.

Pope Francis bows his head in prayer during the opening of the summit on Thursday.

Pope outlines summit roadmap

The Pope then said that he had made a list of 21 "reflection points" that were handed out to the assembly of church leaders.

Among the points was a proposal to raise the minimum age for marriage to 16 years old. Current canon law in the Catholic Church has the minimum age as 14 for females and 16 for males.

Archbishop Charles Scicluna of Malta, an organizer of the summit in Rome, said that conferences of bishops in individual countries have the power to raise the age, but that the Pope wants to make the change part of universal canon law.

Here are the "reflection points" the Pope handed out today to Catholic leaders at the summit on clergy sex abuse pic.twitter.com/Pct0YOpIoD — Daniel Burke (@BurkeCNN) February 21, 2019

Scicluna, the church's top sex abuse investigator, called the guidelines a "roadmap for our discussion," adding that "they are very, very concrete."

The Pope's "reflection points" include preparing a "practical handbook" of guidelines for handling abuse cases when accusations emerge.

Also included are instructions to inform civil authorities and church officials whenever an accusation is made, establishing provisions to include non-clergy experts in investigations, as well as formulating "mandatory codes of conduct" for all church clergy, personnel and volunteers "to outline appropriate boundaries in personal relationships."

More controversially, the Pope proposed that dioceses and Catholic organizations around the world not publish lists of clergy accused of abuse before a preliminary investigation and "definitive" condemnation have occurred.

"The principle of natural and canon law of presumption of innocence must be also be safeguarded until the guilt of the accused is proven," the Pope said in the "reflection points."

Abuse survivors often insist that the public is notified whenever an accusation is made, both to protect the community and to encourage other potential victims to come forward.

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"This seems to say that if a priest or a nun or deacon gets accused they don't tell the parish until the accusation is 'proven,'" said Tim Lennon, of the Survivors Network of those Abused by Priests, who is in Rome participating in vigils with other clergy abuse victims.

"Well, who proves this? The police or the bishops? We've seen for 35 years that bishops often cover up, so no one trusts that they are going to be good arbiters of guilt and innocence."

As the sun set over St. Peter's Basilica, about 20 abuse survivors gathered near the Vatican, where they called on the church to adopt a "zero tolerance" policy towards clergy who abuse children and bishops who cover up the crimes. Some held flags from their home countries and wiped tears from bloodshot eyes.

'A life destroyed': Survivors speak

After the Pope spoke, he and the assembled church leaders watched harrowing video testimonies from several victims of clergy sexual abuse.

One woman, who was not named, spoke of a priest who began sexually abusing her when she was 15.

"This lasted for 13 years," the woman said. "I got pregnant three times and he made me have an abortion three times, quite simply because he did not want to use condoms or contraceptives."

The woman said that the priest would humiliate her, and beat her if she refused to have sex with him.

"I feel I have a life destroyed," she said.

Another survivor of clergy sexual abuse, identified as 53-year-old priest, said another priest molested him when he was a teenager. When he reported the abuse to the local bishop, who he did not name, the bishop "attacked me without trying to understand me."

The priest said that neither the bishop nor the priest he says abused him have answered his letters, even after eight years of waiting.

The last survivor of clergy sexual abuse to speak to the Pope and church leaders said that he had been sexually molested "over a hundred times," an experience that has led to traumas and flashbacks.

When he told church leaders about the abuse, the man said, they "covered (up for) the perpetrators and that kills me sometimes."

"I'll request that the bishops get their act clear because this is one of the time bombs happening in the church of Asia."

The Rev. Hans Zollner, one of the summit's organizers, said at a news conference Thursday that he deliberately selected clergy sexual abuse victims from every continent to speak about their experience to make clear that "this is not a North American or Central European problem."

The "searing, brutal, honest" testimonies, Zollner said, were followed by two minutes of silence in Paul VI Hall in Vatican City, where the summit is being held.

"You could hear, you could see, you could feel that people were in tune with what had been read (and) what had been said," Zollner said.

But differences soon emerged among the bishops in their small group discussions, said Archbishop Mark Coleridge of Australia.

"It was immediately evident in the discussion with bishops from Africa and Asia saying, 'Well why are we talking about sexual abuse? Because abuse in my country takes many forms: child labor, child soldiers. Why this obsession with sexual abuse?'"

Reaching consensus on how to approach clergy abuse "is going to be one of the big challenges of the meeting," Coleridge said at the news conference.

A cardinal holds the liturgy booklet during the opening of the Vatican meeting.

Crucial moment for church

After the Pope spoke on Thursday morning, Cardinal Luis Antonio Tagle, the Archbishop of Manila in the Philippines, gave a spiritual talk centered on healing wounds and providing justice for survivors of sexual abuse.

"The abuse of minors by ordained ministers has inflicted wounds not only on the victims, but also on their families, the clergy, the church, the wider society, the perpetrators themselves and the bishops," Tagle said. "But it is also true, we humbly and sorrowfully admit, that wounds have been inflicted by us bishops on the victims and in fact the entire body of Christ.

"Our lack of response to the suffering of victims," Tagle continued, "even to the point of rejecting them and covering up the scandal to protect perpetrators and the institution has injured our people, leaving a deep wound in the relationship with those we are sent to serve."

On Wednesday, summit organizers met with abuse survivors from around the world, saying afterward that the meeting will help them "better understand the gravity and urgency of the difficulties" church leaders will face during the four-day summit.

The meeting centers around themes: responsibility on Thursday, accountability on Friday and transparency on Saturday. On Sunday, more than 100 bishops from around the world, as well as other Catholic leaders, will gather for Mass in Sala Regia, an ornate hall in the Vatican's Apostolic Palace.

Pope Francis has sought to deflate expectations for the meeting, officially called, "Protection of Minors in the Church." The goal, he said, is to hear abuse survivors speak about their experiences, to teach bishops about the church's procedures to deal with abusive clergy and to seek forgiveness.

In his Angelus address on Sunday, Francis asked Catholics to pray for the meeting, an event that he said he wants "to be a powerful gesture of pastoral responsibility in the face of an urgent challenge of our time."

Other prominent Catholics also have described the summit in urgent terms, saying the church's credibility is on the line.

"My hope will be that people see this as a turning point," Cardinal Blase Cupich of Chicago, a member of the organizing committee, said Monday at a news conference. "This is not the endgame. No one can say there will be no more abuse in the church or the world, but people will be held accountable."

Catholic leaders at this week's meeting come from almost every part of the globe, with 36 from Africa, 24 from North and South America, 18 from Asia, 32 from Europe and four from Oceania, organizers say.

In addition to Roman Catholic bishops, there will be 14 leaders of Oriental Catholic churches, 22 superiors general of religious orders and 14 members of the Vatican's own bureaucracy, including the heads of 10 departments.