One woman told the BBC she had had two sightings, both times between three o'clock and six o'clock in the morning.
Church officials in southern Egypt say thousands of Christians have been converging on the town of Assiut after reported sightings of the Virgin Mary.
The secretary of the Council of Churches in Assiut told the BBC the town had never experienced anything like it.
He said people had been sleeping in the streets around the Church of St Mark, where the apparitions happened, and standing on rooftops to catch a glimpse.
Assiut has been best known until now as a stronghold of Islamic militancy during the 1990s.
Light, incense and pigeons
Christians in Assiut say the first apparition came two-and-a-half weeks ago but that there have since been several more.
One woman told the BBC she had had two sightings, both times between three o'clock and six o'clock in the morning.
She said she had seen the Virgin Mary with outstretched hands and a light emanating from them, accompanied by a smell of incense and large numbers of pigeons.
The birds seem to be a common element of the sightings.
The secretary of the Assiut Council of Churches, Father Mina Hanna, said other people had seen a big white, brightly lit pigeon appearing and disappearing - but he said the apparitions were different each time.
He would no reveal if he had had a personal experience himself.
'Blessing'
But another priest has been quoted as saying he spent the entire night awake and saw only ordinary pigeons, and that that was not a miracle.
None the less, Father Hanna said the reported sightings were "a blessing" for Assiut.
The priest said relations between Christians and Muslims were now very good and that the sightings had made people of both religions happy.