Pope Francis has held a private meeting with victims of clerical sexual abuse during a five-day visit to Portugal.

In a statement, the Vatican said the gathering had been held on Wednesday in an "atmosphere of intense listening".

A report this year concluded that at least 4,815 children had been abused in Portugal and that the Church had sought "systematically" to conceal the issue.

At an evening service in Lisbon, the Pope said the Church must listen to "the anguished cry of the victims".

He added that the scandal "calls us to a humble and ongoing purification" and that widespread anger over it had contributed to a "growing detachment from the practice of the faith".

The meeting, held at the Holy See's diplomatic mission in Portugal, included 13 abuse victims and lasted more than an hour, the Vatican said.

Officials of the Portuguese Church responsible for the protection of minors were also in attendance.

In February, an independent commission set up by the Catholic Church in Portugal published a report documenting the experiences of 564 people who said they had been abused by priests or other Church officials.

The exercise - similar to audits carried out elsewhere in Europe and the Americas - looked at cases dating back to 1950.

In many cases, testimony pointed to other minors having been abused, hence the estimate of thousands of victims in total.

Presenting the report, the commission's president, child psychiatrist Pedro Strecht, said the estimate represented the "absolute minimum" and that "these numbers are just the tip of the iceberg".

Paying tribute to those who had contacted the commission to provide testimony, he said they had "dared to give a voice to silence".

Pope Francis is in Portugal to mark World Youth Day, a week-long festival of religious and cultural events staged by the Church every few years in cities around the world.