Pope Francis says pilgrimages can be organized to a Bosnian shrine where the Virgin Mary is reported to have appeared, but the Vatican is stressing that no decision has yet been taken on whether the apparitions in Medjugorje are authentic.

Vatican spokesman Alessandro Gisotti said Sunday that "care must be taken to avoid interpreting these pilgrimages as authentication" of the visions that six youths said they experienced there in 1981.

The Vatican says those events "still require study by the Church."

Millions of Catholics have flocked to the site. But despite years of study, the Vatican has never declared the visions as authentic, unlike the phenomenon of visions of Mary at Fatima, Portugal, or Lourdes, France, two other immensely popular pilgrimage destinations.

Local Bosnian bishops have questioned the interests of the "seers."