Philadelphia's Catholic archbishop says Pope Francis told him he's coming to the city next year for the World Meeting of Families conference. But Vatican and Archdiocesan officials say they won't confirm the visit.

Philadelphia Archbishop Charles Chaput made the announcement during a Thursday mass at a conference of Native-American Catholics in Fargo, North Dakota, the Catholic News Service reports.

"Pope Francis has told me that he is coming," the agency quoted the archbishop as saying to that conference's attendees before inviting them to attend as well.

Chaput then went on to say the pope will attend three days of the conference -- Friday, Saturday and Sunday -- which is taking place from September 22 through 27.

But despite the archbishop's confirmation, conference officials and The Vatican say no official decision has been made.

"While Archbishop Chaput's comments do not serve as official confirmation, they do serve to bolster our sincere hope that Philadelphia will welcome Pope Francis next September," a statement released by the archdiocese said.

Archdiocesan spokesman Kenneth Gavin said Chaput was not misquoted, but that nothing is official until written confirmation is received from the Vatican.

Should the pope come to Philadelphia, it will be not only his first visit to the city, but also his first time in the United States as the Holy Father.

City, state and church officials went to The Vatican this spring to meet with church officials and pitch for the pope's attendance at the event. Pontifical Council for the Family Council President Archbishop Vincenzo Paglia came to Philadelphia for a site visit a few months later.

Chaput had said he believed the pope would visit, but was awaiting official confirmation.

The World Meeting of Families is a triennial conference that draws Catholics from around the world. Officials estimate up to 2 million people could attend the conference and take part in a mass led by Francis. Church officials say such a mass could be the largest event ever held in North America.