An official inquiry into the Roman Catholic Church in Switzerland has identified nearly 1,000 cases of sexual abuse since 1950.
Many involved children and 56% of the victims were male, the report said. The vast majority of the accused were men.
Researchers from the University of Zurich also found evidence of a “widespread cover up”.
“The cases we identified are without a doubt only the tip of the iceberg,” said the study’s leads.
Monika Dommann and Marietta Meier compiled the report following a year-long investigation, which was commissioned by Church authorities.
They were given access to Church archives and also held interviews with several people, including those affected by sexual abuse.
However, they said “numerous” other documents had not yet been made available.
The researchers also found evidence that records had been destroyed at two dioceses and that not all reported cases of sexual abuse were written down and consequently archived.
“Given what we know from research on the dark figure of crime, we assume that only a small percentage of cases was ever reported in the first place,” said Ms Dommann and Ms Meier.
More than half of the cases identified happened during instances where pastoral case was taking place – particularly during confession, altar service and religious education in children’s clubs and associations.
A further 30% of abuse was found to have been committed in institutions including Catholic children’s homes, day schools and boarding schools.
As well as documenting instances of sexual abuse, the researchers also looked at how Church officials dealt with these cases and said many were “kept secret, covered up or trivialised”.
Their report criticised various officials, including bishops, for not doing more to help those affected.
Clerics accused of committing abuse were found to have been “systemically” reassigned to other posts by those in positions of power, sometimes abroad, to avoid being prosecuted.
“In doing so, the interests of the Catholic Church and its dignitaries were given precedence over the welfare and safety of parishioners.”
The researchers said this attitude did not change until the 21st Century, when various sex abuse scandals began emerging.
“Unfortunately, the results of the preliminary investigation confirm what we have observed and, in some cases, are still experiencing,” groups representing sexual abuse victims said in a statement in response to the report.
“For decades, the authorities of the Catholic Church in Switzerland have covered up these crimes, protecting the perpetrators and the reputation of their institution at the expense of the victims who were silenced.”
The president of the Swiss Bishops’ Conference, the governing body of the Catholic Church in Switzerland, told a press conference on Tuesday that the organisation “gave countless excuses” and that its actions “fell short of what the victims are entitled to.”
“We search for words and know that we won’t find the right ones,” said Renata Asal-Steger.
Church authorities said that they would fund a follow up project by the University of Zurich, which is due to begin in 2024.