The tree was decorated with ornaments made by children receiving treatment in Italian hospitals.

The huge nativity scene, with terracotta figures depicting the birth of Jesus Christ, installed alongside, is of a traditional design from Italy's Napoli region.

The pope said the traditional seasonal event was a sign of "compassion" and that Christmas provides a chance "to be more attentive to the needs of the poor and of those who, like Jesus, do not find anyone to welcome them".

In the evening thousands of people came to see the tree lit up.