VATICAN CITY (AP) - Pope Francis has made an impromptu appearance near the Vatican, prompting cheers of "Francesco" from the crowd.

More than two hours ahead of his appointment with the faithful from his studio window overlooking St. Peter's Square, Francis walked to an open gate near the edge of Vatican City, ahead of a Mass he was celebrating in the parish church for Vatican residents.

In keeping with his informal style, Francis, in simple white robes, then went over to the chief of his security detail and appeared to indicate he wanted to greet two priests in the crowd, who approached and embraced him. Francis then went to celebrate Mass in St. Anna's church.

Hundreds were outside the gate when Francis appeared, but 100,000 are expected for the window appearance.