Belgium's prime minister blasted Pope Francis for the Catholic Church's horrific legacy of clerical sex abuse and cover-ups here, demanding “concrete steps” to come clean with the past and put victims' interests ahead those of the institution in a blistering welcome at the start of Francis' visit on Friday.

The speech by Prime Minister Alexander De Croo was one of the most pointed ever directed at the pope during a foreign trip, where the genteel dictates of diplomatic protocol usually keeps outrage out of the public remarks. But even King Philippe had strong words for Francis, demanding the church work “incessantly” to atone for the crimes and help victims heal.

Their tone underscored just how raw the abuse scandal still is in Belgium, where two decades of revelations of abuse and systematic cover-ups have devastated the hierarchy's credibility and contributed to an overall decline in Catholicism and the influence of the once-powerful Catholic Church.

Francis applauded at the end of De Croo's speech and was expected to meet with victims in private later Friday. "This is our shame and humiliation,” he said in an improvised response.

“Today, words alone do not suffice. We also need concrete steps,” De Croo told Francis and an audience of royals, church officials, diplomats and politicians at Laeken Castle, the residence of Belgium's royal family.

“Victims need to be heard. They need to be at the centre. They have a right to truth. Misdeeds need to be recognised,” he said. “When something goes wrong we cannot accept cover-ups,” he said. “To be able to look into the future, the church needs to come clean on its past.”

Revelations of Belgium's horrific abuse scandal have dribbled out in bits over a quarter century, punctuated by a bombshell in 2010, when the country's longest-serving bishop, Bruges Bishop Roger Vangheluwe, was allowed to resign without punishment after admitting he had sexually abused his nephew for 13 years.

Francis only defrocked Vangheluwe earlier this year, in a move clearly designed to remove a lingering source of outrage among Belgians before his visit.

Two months after Vangheluwe resigned, Belgian police staged what were then unprecedented raids on Belgian church offices, the home of recently retired Archbishop Godfried Danneels, and even the crypt of a prelate — a violation the Vatican decried as “deplorable.”

Danneels was then caught on tape trying to persuade Vangheluwe's nephew to keep quiet until the bishop retired. Finally, in September 2010 the church released a 200-page report that said 507 people had come forward with stories of being molested by priests, including when they were as young as 2. It identified at least 13 suicides by victims and attempts by six more.

Victims and advocates say those findings were just the tip of the iceburg and that the true scope of the scandal is far greater. Police eventually returned the documentation that was seized in the 2010 raids to the church, scuttling hopes for criminal investigations.

Despite everything that was known and already in the public domain, the scandal reared its head in a shocking new way last year, when a four-episode Flemish documentary, “Godvergeten” (Godforsaken) aired on public broadcaster VRT.

For the first time, Belgian victims told their stories on camera one after another, showing Flemish viewers the scope of the scandal in their community, the depravity of the crimes and their systematic cover-up by the Catholic hierarchy.

Amid the public outrage that ensued, both a Flanders parliamentary committee and Belgium's federal parliament opened official inquests last year. A follow-on investigation announced this week will look into whether any external pressures led to the collapse of the criminal investigation.

Significantly, both King Philippe and De Croo made their toughest remarks about abuse in Dutch — the language spoken in the once-staunchly Catholic Flanders where the abuse cases have gained the most notoriety — while the more neutral parts of their speeches were delivered in French and German.

De Croo's speech was outside typical Vatican protocol, which normally would have seen only the king address the pope. As occurred in Canada, when Prime Minister Justin Trudeau addressed the pope alongside the country's governor-general, De Croo's office requested that he be able to speak, officials said.

The pope also referred to abuse in his remarks, insisting that the church was “addressing firmly and decisively” the problem by implementing prevention programs, listening to victims and accompanying them to heal.

But after the astonishing dressing down by the prime minister and king, Francis went off-script to express the shame of the church for the scandal and voice his commitment to ending it.

“The church must be ashamed and ask for forgiveness and try to resolve this situation with Christian humility and put all the possibilities in places so that this doesn't happen again,” Francis said. "But even if it were only one (victim), it is enough to be ashamed."

Victims, however, have demanded the church do far more, including implementing robust reparations programs to compensate them for their trauma and pay for the lifelong therapy many need. Some penned a letter demanding such a reparations program, which they planned to deliver to Francis in their private meeting.

The prime minister, king and pope also referred to a new church-related scandal rocking Belgium, over so-called “forced adoptions,” which echoed earlier revelations about Ireland's so-called mother and baby homes.

After World War II and through the 1980s, many single mothers were forced by the Belgian church into offering their newborns up for adoption. Often they barely saw their babies before nuns took them away, and the babies were then placed for adoption, with money changing hands.

For those adopted, it is close to impossible now to find out who their birth mothers were, since the records have long ago disappeared.

Francis said he was “saddened” to learn of these practices, but said such criminality was “mixed in with what was unfortunately the prevailing view in all parts of society at this time.”

“Many believed in conscience that they were doing something good for both the child and the mother,” he said, referring to the social stigma of an unwed mother in a Catholic country. He said he prayed that the church would “bring clarity” to the problem and not manipulate the Gospel to “draw inauthentic conclusions that cause suffering and exclusion.”

Belgium's caretaker Justice Minister Paul Van Tigchelt has called the forced adoptions ''horror practices by the church.” No formal figures are available, but the HLN media group that brought the issue to the fore again last year estimated it affected up to 30,000 babies over the period.