Pope Francis inauguration Mass celebrated in Vatican. (video)

The inauguration Mass for Pope Francis has been held in St Peter's Square in Rome, marking the start of his papacy.

Francis earlier toured the square in an open-topped vehicle, descending to bless pilgrims behind the barriers.

His homily called on global leaders and all people of the world to protect the weak and the poor. Tens of thousands of pilgrims attended the Mass.

Francis was elected by a conclave of cardinals last week to take over from Benedict XVI.

Benedict became the first pontiff in 600 years to abdicate last month. Citing his age, 85, he said he could no longer continue in the post.

The first pontiff from the Americas, Francis has suggested he will take a more modest approach than predecessors.