Pope Francis is coming to the United States.

Francis confirmed Monday that he will travel to Philadelphia next September for the World Meeting of Families, a conference held every three years in a different city to celebrate the importance of family.

Francis’ announcement, at an interreligious Vatican conference on traditional family values, ended months of lobbying and speculation.

Philadelphia Mayor Michael Nutter, Pennsylvania Gov. Tom Corbett and Philadelphia Archbishop Charles Chaput, the conference’s organizer, met with Francis at the Vatican and personally invited him to the city in March.

Vatican officials toured the city in May and President Barack Obama, U.N. Secretary-General Ban Ki-moon and Congress have extended invitations.

Just last week, more than 10,000 Philadelphia Catholic school children sent handwritten notes encouraging Francis to make the visit.

The pope is also expected to visit New York and Washington, but Vatican officials Monday would not confirm those legs of the trip.

The pope ‘‘wanted to guarantee his presence to the organizers of the World Meeting of Families in Philadelphia 2015, but for the rest I have nothing to say, no concrete information to give,’’ the Vatican spokesman the Rev. Federico Lombardi told reporters.

The Vatican’s envoy to the United Nations last week strongly hinted that Francis would visit New York to address world leaders at the General Assembly, saying the coming 70th anniversary of the world body would be ‘‘the ideal time.’’

Francis, making just the second papal visit to Philadelphia and his first visit to the U.S. as pope, is expected to participate in the conference’s closing events and celebrate a Mass on the Benjamin Franklin Parkway.

Details of Francis’ itinerary will not be finalized until next spring or summer, conference organizers said.

Francis’ visit will come just weeks before the 50th anniversary of the first papal visit to the U.S. Pope Paul VI addressed the United Nations General Assembly, attended the New York World’s Fair and celebrated Mass at Yankee Stadium in October 1965.

(AP)