(CNN) -- Pope Francis spoke out against sexual abuse by Catholic clergy on Monday and said he plans to meet with victims in early June. In a wide-ranging talk with reporters, he also discussed celibacy in the clergy, saying it's not dogma so "the door is always open." The Pope fielded questions on these subjects during an informal chat with reporters. He simply walked to the back of the papal airplane, sat down with a group of journalists and took questions for about 45 minutes, answering in Italian. When the Vatican spokesman suggested he stop after half an hour to rest, the Pope indicated he was happy to continue. Such informality has become a hallmark of Pope Francis.
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NEW: Pope says "the door is always open" on celibacy discussions
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The meeting would mark his first with a group of abuse victims
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Speaking to reporters aboard the papal plane, the pontiff called for zero tolerance
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While in Mideast, he invites Israeli, Palestinian leaders to Vatican to pray
During that trip, the Pope extended an invitation to the leaders of Israel and the Palestinian Authority to travel to the @placeholder for peace talks.