Pope Francis has washed the feet of prisoners in a youth detention centre near Rome as part of the Holy Thursday service.
The Christian ritual takes place on the Thursday before Easter to commemorate Christ's Last Supper.
Thousands of pilgrims and tourists are arriving in Rome to attend ceremonies during the holy week ahead of Easter.
The new leader of the world's 1.2 billion Roman Catholics has brought a new sense of simplicity to the Vatican, the BBC reports. He broke with tradition for the foot-washing ceremony, which is normally performed on lay people in one of Rome's basilicas.
During the intimate service at Casal del Marmo, Francis washed and kissed the feet of 12 young detainees to replicate the Bible's account of Jesus Christ's gesture of humility towards his 12 apostles on the night before he was crucified.
The inmates included two girls, one Italian Catholic and one of Serbian Muslim origin, local prison ombudsman Angiolo Marroni said before the ceremony.
The pontiff told inmates that Jesus had washed the feet of his disciples in a gesture of service, Vatican Radio reported. After the ritual, he gave Communion to the inmates and prison workers.
In total, around 10 girls and 40 boys from different nationalities and diverse religious confessions were taking part in Thursday's Mass.
Earlier, during a homily at St Peter's Basilica, the Pope urged priests to do less "soul-searching" and engage more with parishioners.
"It is not in soul-searching... that we encounter the Lord," he told hundreds of cardinals, priests and bishops in St Peter's Basilica.
"We need to go out... to the outskirts where there is suffering, bloodshed, blindness that longs for sight and prisoners in thrall to many evil masters."
Worshippers should "leave Mass looking as if they had heard good news", he said.
Easter is the most important festival in the calendar of the Catholic Church.
On Good Friday evening the Pope will carry a wooden cross and pray at a ceremony at Rome's ancient amphitheatre, the Colosseum, commemorating Jesus' crucifixion.
On Saturday evening he will celebrate the main Easter Vigil Mass in St Peter's Basilica, while on Easter Sunday morning, Francis will deliver his first "Urbi et Orbi" message to the city of Rome and to the world.
