Pope Francis strongly denounced clerical sex abuse of children, saying that such abuse will not be tolerated and announcing a special Mass for abuse victims, as well as efforts to investigate offenders.

"There will be no preferential treatment when it comes to child abuse," the Pope said, declaring abuse a "very serious problem."

"A zero tolerance approach needs to be adopted with regards to this issue."

"When a priest commits abuse, he betrays the Lord's body," he stated May 26. "A priest must guide children towards sainthood. And the child trusts him. But instead, he abuses him or her. This is very serious. It's like celebrating a black mass!"

"Instead of steering him or her towards the sainthood you create a problem that will stay with him or her for all of his or her life," he added, according to the Italian newspaper La Stampa.

The Pope's comments came during a press conference on his May 26 return flight from the Holy Land.

He announced that there will be a Mass for some abuse victims at his residence at Casa Santa Martha "soon" and he will also meet with these victims.

Cardinal Sean O'Malley of Boston will assist in planning the meeting, the Archdiocese of Boston reports.

Cardinal O'Malley helped organize a similar meeting between Pope Benedict XVI and abuse victims during the 2008 papal visit to the U.S. He is a member of the Pontifical Commission for the Protection of Minors as well as the Council of Eight Cardinals which was formed by Pope Francis to advise him on matters of Church reform and governance.

Pope Francis also noted that three bishops are under investigation for problems relating to child abuse, one of whom has been convicted and awaiting punishment. Concerns had been raised in the past about some bishops failing to adequately deal with priests accused of abuse or enforce church law regarding such allegations.

During the flight, Pope Francis also addressed financial scandals linked to the Institute for the Works of Religion, informally known as the Vatican Bank.

He said the newly formed Secretariat for the Economy, headed by Australian Cardinal George Pell of Sydney, will help prevent scandals and problems.

Some 1,600 illegitimate accounts have already been closed, he said, adding that the reform process must be "ongoing."

Pope Francis also spoke about the reform of the Roman Curia, the bureaucracy that helps the Holy Father run the Vatican. Two work sessions on the reform efforts will be held in the coming months, he said, and the merging of Vatican dicasteries is under consideration.

"We have done a great deal," he said of reform efforts.

"The path of persuasion is very important. There are some people who don't understand. But I am happy, we have worked hard," he added.