Vatican City, Nov 17, 2014 / 01:11 am

Updated November 17, 2014 at 6:25a.m. MST. Adds comments from Vatican spokesman Fr. Federico Lombardi SJ at paragraphs 9-10.

Pope Francis on Monday officially announced that he will visit the U.S. in September 2015, including a visit to the World Meeting of Families in Philadelphia.

"I wish to confirm, if God wills it, that in September of 2015 I will go to Philadelphia for the Eighth World Meeting of Families," he announced at Vatican City's Synod Hall Nov. 17 during his remarks at an international colloquium on the complementarity of man and woman.

The Philadelphia World Meeting of Families will take place from Sept. 22-27. Even before the Pope's announcement, the meeting was expected to draw tens of thousands of people. Archbishop Charles J. Chaput of Philadelphia had told a gathering of Catholic bishops last week that a papal visit would likely result in crowds of about 1 million.

A global Catholic event, the world meeting seeks to support and strengthen families. St. John Paul II founded the event in 1994, and it takes place every three years.

Archbishop Chaput had previously hinted that Pope Francis would attend the 2015 meeting, although he cautioned that the visit had not been officially confirmed. In March 2014, a Pennsylvania delegation including Pennsylvania Gov. Tom Corbett and Philadelphia mayor Michael Nutter visited the Vatican to help encourage the Pope to visit the U.S.

On Thursday, Archbishop Bernardito Auza, the head of the Holy See's permanent observer mission to the United Nations, told the Associated Press "if he comes to Philadelphia, he will come to New York."

The 70th anniversary of the U.N.'s founding would be "the ideal time" for a papal visit, the archbishop said Nov. 13. Next year also marks the 50th anniversary of Pope Paul VI's 1965 visit to the U.N., the first such visit from a Pope.

In August, on his return flight from South Korea, Pope Francis said he wanted to visit the U.S. in 2015 for the Philadelphia gathering. He also noted that he had received invitations from President Barack Obama, Congress and U.N. Secretary-General Ban Ki Moon, as well as from Mexico.

However, despite the anticipation of the Pope's possible visit to New York and Washington while in the U.S., Vatican spokesman Fr. Federico Lombardi S.J. told journalists shortly after the announcement that as of now nothing else is confirmed.

The Pope, he explained, "didn't say anything about any other steps or moments in his trip to America. He guaranteed his presence to the organizers of the World Day for Families, but as for the rest, I have no concrete information."

Pope Francis has visited the Holy Land and Albania as well as South Korea. He will visit France and Turkey in November, and Sri Lanka and the Philippines in January 2015. He will return to France for a longer visit in 2015.

In June, the Pope accepted an invitation to visit Mexico, though a date for the visit was not announced.

The World Meeting of Families will take place shortly before the October 2015 meeting of the Synod of Bishops on the Family, which will discuss the mission of the family in the Church and in the world.

At the last World Meeting of Families in Milan, Italy, in 2012, more than 1 million people representing 153 nations attended a papal Mass with Pope Benedict XVI.

The 2015 meeting's theme is "Love is Our Mission: The Family Fully Alive." The meeting will include many speakers and breakout sessions. Keynote speakers include Cardinal Sean O'Malley of Boston, Cardinal Luis Antonio Tagle of the Philippines, Cardinal Robert Sarah, professor Helen Alvare, and Dr. Juan Francisco de la Guardia Brin and Gabriela N. de la Guardia.

The Philadelphia meeting will mark the first time that the event will be held in the United States.

Registration for the 2015 World Meeting of Families began on Nov. 10.

The World Meeting of Families website is www.worldmeeting2015.org. It is on Facebook at https://www.facebook.com/WorldMeeting2015 and on Twitter at https://twitter.com/WMF2015.