Thousands of Christian pilgrims gathered on Saturday in Jerusalem for an ancient fire ritual that celebrates Jesus' resurrection.

The pilgrims crowded Saturday into the Church of the Holy Sepulcher, where many Christian traditions hold that Jesus was crucified, buried and resurrected.

During the annual ceremony, top Eastern Orthodox clerics enter the Edicule, the small chamber marking the site of Jesus' tomb.

They will emerge after some time to reveal candles lit with "holy fire…" said to be miraculously lit as a message to the faithful from heaven. The details of the flame's source is a closely guarded secret. The flames will be passed from believer to believer.

Eastern Orthodox churches celebrate Easter this week using the older Julian calendar.