The pontiff made his remarks while returning from an official visit to South Korea.
The five-day World Meeting of Families is scheduled to begin September 22, 2015. If the pope says Mass at its close, as is traditional, city officials predict his presence would draw well in excess of one million visitors. Francis has not visited the United States since his election to the pontificate in March 2013.
Ken Gavin, spokesman for the Archdiocese of Philadelphia, which is hosting the World Meeting in conjunction with the Holy See, cautioned Monday that Francis' latest remarks still do not serve as the Vatican's official confirmation of his intent to attend the World Meeting.
"I've corroborated with the Vatican Press Office that his remarks constitute a strong desire on the part of the Holy Father to be here," Gavin wrote in an e-mail, "but it is still not an official confirmation," which is expected about six months prior to the event.
En route to South Korea last week, Francis, who is from Argentina, replied " sí" when a TV reporter asked if he expected to visit Philadelphia next year.
And late last month, Catholic News Service reported that Archbishop Charles J. Chaput had told a gathering of American Indians in North Dakota that Francis planned to spend several days in Philadelphia.
A day later, the Vatican Press Office said the pope was "carefully considering" invitations from several cities in the United States, including Philadelphia, but that there were "no concrete plans" made as yet.