Pope Francis on Tuesday acknowledged that Catholic priests and bishops had sexually abused nuns, and in one case had kept them as sex slaves, BBC reported.

“There are some priests and also bishops who have done it,” the head of the Catholic Church said in response to a question on the abuse of nuns. He was speaking on the return flight from his trip to the United Arab Emirates, AFP reported.

A Vatican magazine, Women Church World, in its February issue reported on clergy members sexually abusing nuns, leaving them forced to have abortions or giving birth to the children, according to CBS News.

Francis said the problem could be found “anywhere” but was prevalent in “some new congregations and in some regions”. “I think it’s still going on, because it’s not something that just goes away like that. On the contrary,” he said, adding that the Catholic Church had suspended several clerics and the Vatican has been “working [on the issue] for a long time”.

The pontiff said his predecessor, Pope Benedict, was forced to shut down a congregation of nuns who were being abused by priests. “Pope Benedict had the courage to dissolve a female congregation which was at a certain level, because this slavery of women had entered it – slavery, even to the point of sexual slavery – on the part of clerics or the founder,” BBC quoted Francis as saying.

Alessandro Gisotti, interim director of the Vatican Press Centre, later told CBS News that the congregation of nuns dissolved under the previous pope was the Community of St. Jean in France.

The pope said the Catholic Church, “shouldn’t be scandalised by this,” and that “there are steps in a process.”

Bishop in India accused of raping nun

In India, a bishop was arrested after a nun accused him of raping her 13 times between 2014 and 2016 at a convent in Kerala’s Kottayam. Franco Mulakkal was arrested on September 21 after three days of questioning. On October 15, the Kerala High Court granted him conditional bail, and he was released the following day. Mulakkal, who returned to Jalandhar on October 17, denied all charges.

An internal investigation by the Missionaries of Jesus in September found Mulakkal to be innocent. The organisation has also attempted to malign the complainant repeatedly, once alleging that she was in a relationship with a taxi driver.