Rome (CNN) Pope Francis, speaking on the final day of a historic summit on clergy sexual abuse, called priests and other Catholics who abuse children "tools of Satan," but offered no concrete steps to address the church's massive and morally damning abuse crisis.

"The brutality of this worldwide phenomenon becomes all the more grave and scandalous in the church, for it is utterly incompatible with (its) moral authority and ethical credibility," the Pope said in a speech in Vatican City on Sunday.

"Consecrated persons," he continued, "chosen by God to guide souls to salvation, let themselves be dominated by their human frailty or sickness and thus become tools of Satan."

The Pope's speech, delivered at the end of Mass at Sala Regia in the Apostolic Palace, came at the end of an unprecedented gathering of 190 Catholic leaders, including 114 bishops from around the world, to address a clergy sexual abuse scandal that stretches across several continents.

Pope Francis attends a Eucharistic celebration at the Regia Hall of the Apostolic Palace in the Vatican on Sunday.

In his wide-ranging speech on Sunday, Francis framed the church's abuse crisis within the wider context of society, even saying that pagans, in history, had "sacrificed children" in rituals.

"We are thus facing a universal problem," the Pope said, "tragically present almost everywhere and affecting everyone. Yet we need to be clear, that while gravely affecting our societies as a whole, this evil is in no way less monstrous when it takes place within the church."

The Pope also appealed for an "all-out battle" against child abuse.

Anger over inaction

In St. Peter's Square on Sunday morning, many expressed anger and frustration over the Pope's address and the lack of concrete results from the summit. Dozens of survivors of sexual abuse perpetrated by Catholic clergy have also been in Rome this week to protest and offer testimonies about their experiences In St. Peter's Square on Sunday morning, many expressed anger and frustration over the Pope's address and the lack of concrete results from the summit.

"I'm going to go away bitterly bitterly disappointed but not entirely surprised," said Peter Saunders, a former member of the Pope's commission on the protection of minors. "I can't say that I honestly thought the world was going to change -- because I know this institution too well -- and it seems incapable of change. And yet, it could do it."

"So will the Pope act?" Saunders said. "He had his chance. I think history will judge him."

Virginia Saldanha, a member of the group Ending Clergy Abuse, said she was angered by the Pope's address on Sunday morning.

"I was very angry because I see just nice words over here, no concrete framework for implementation," said Saldanha, who is from India.

"He says a change of mentality is needed to combat a defensive and reactive approach. You mean all these years when survivors were pleading with the church, they didn't know it was wrong?"

The four-day summit has included two speeches by the Pope, talks outlining best practices and small-group discussions among bishops.

John Allen, a Vatican analyst for CNN, said that, while Pope Francis is often seen as a charismatic champion of underdogs around the world, that side of the pontiff was seldom seen during the four-day summit.

"He is typically at his best when he speaks spontaneously and from the heart. For whatever reason the world didn't see much of that Pope Francis during the four days of his anti-abuse summit. Instead what the world saw was largely familiar boilerplate rhetoric that church officials have used about the abuse crisis since its onset more than three decades ago," Allen said.

Francis began the unprecedented summit on Thursday by saying that Catholics are not looking for simple condemnation , but concrete actions.

"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."

What next?

The bishops have discussed several measures, including a proposal to hold bishops accountable and lift the "Pontifical Secret" that often keeps abuse victims in the dark about how their church trials are processing. But they did not appear to vote on or immediately adopt any new measures.

Cardinal Blase Cupich of Chicago said on Saturday there was a kind of consciousness raising about clergy sexual abuse, though, among some of the 116 bishops from around the world.

"What is so very noticeable is the movement in attitude of people, especially among people who think this isn't happening in their country. There is real ownership now that this is a global issue."

Cupich also said there is momentum among top Catholic officials to revoke or reform the Pontifical Secret with regard to abuse cases.

After the summit's conclusion, Cardinal Daniel DiNardo, president of the U.S. Conference of Catholic Bishops, said he "felt affirmed in the work that is underway."

DiNardo said presenters spoke about creating a code of conduct for bishops, making the church more transparent and establishing protocols for handling accusations against bishops, a proposal made by the US bishops' conference in November before the Vatican asked it to stand down.

"Enhanced by what I experienced here, we will prepare to advance proposals, in communion with the Holy See, in each of these areas so that my brother bishops can consider them at our June General Assembly," DiNardo said.

At a press conference on Sunday, the Rev. Federico Lombardi, the summit's moderator, said the church was "committed to translating into concrete action" the meetings' themes of responsibility, accountability and transparency.

"We will return to our dioceses and communities in various parts of the world with a deeper understanding of the terrible crimes of sexual abuse against minors committed by members of the clergy," he said.

Lombardi also outlined three "first steps" the Vatican will be taking in the near future: a new papal decree "on the protection of minors and vulnerable persons" for members of the church who live and work in Vatican City; a handbook for bishops on how to handle cases of clergy sexual abuse; and the creation of task forces to help bishops' conferences and dioceses around the world implement guidelines.

All were in the works well before this week's summit, Lombardi acknowledged.

Lombardi also said top Vatican officials will meet Monday morning to follow up on measures discussed during the summit.

Some church experts, though, said the meeting failed to meet expectations.

"This summit was full of promising rhetoric about reform," said Allen. "What it did not provide is a single new concrete detail about what reform would mean."