Pope Francis to celebrate Palm Sunday Mass

Pope Francis is to begin the Catholic Church's most important liturgical season with a Palm Sunday Mass in Rome.

Tens of thousands of pilgrims are expected in St Peter's Square for the Mass that marks the start of Holy Week.

Sprigs of olive trees will be distributed to the faithful in remembrance of Jesus' triumphant entry into Jerusalem before his crucifixion.

The run-up to Easter is considered the most important week in the calendar of the Roman Catholic Church.

After Sunday's Mass, the Pope will lead six more liturgies during the week, culminating with the Easter Sunday Mass and Urbi et Orbi blessing.

What the newly-elected Pope says during these services will take on added significance coming at the start of his pontificate, says the BBC's David Willey in Rome.