Pope Francis has washed and kissed the feet of 12 detainees in a youth detention centre near Rome as part of the Maundy 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.
In a homily, Pope Francis earlier urged priests to do less “soul-searching” and engage more with parishioners.
“It is not in soul-searching… that we encounter the Lord,” the Pope 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 added.
During Thursday’s intimate service, Pope 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 12 prisoners included two girls, one Italian Catholic and one of Serbian Muslim origin, local prison ombudsman Angiolo Marroni said ahead of the ceremony.
Some of the prisoners volunteered to have their feet washed, while others were given an invitation to help them overcome their embarrassment, the Catholic News Agency quoted the prison chaplain as saying.
In total, around 10 girls and 40 boys from different nationalities and diverse religious confessions were taking part in Thursday’s Mass at Casal del Marmo on the outskirts of Rome.
The newly-elected Pope has brought a new sense of simplicity to the Vatican.
He has broken with tradition for the foot-washing ceremony, which is normally performed on lay people in one of Rome’s basilicas.
Pope Benedict XVI visited the centre in 2007, but not for the Holy Thursday Mass. Only for the first two years of his pontificate did he perform the feet-washing himself, after which the task was delegated to priests.
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 Pope Francis will celebrate the main Easter Vigil Mass in St Peter’s Basilica.
And on Easter Sunday morning, Pope Francis will deliver his first “Urbi et Orbi” message to the city of Rome and to the world.
During his inaugural general audience on Wednesday, Pope Francis called for an immediate political solution to the conflict in the Central African Republic after last weekend’s coup.