Wearing nothing but a backpack, the naked man runs through the congregation shouting and waving his arms as members of security attempt to grab hold of his rucksack.
The man in the footage was identified as Luis Carlos Giampoli, a 44-year-old nurse from Brazil.
In the footage, he waves his arms in the air and reportedly shouts "Dear brothers and sisters, I'm from Brazil!"
According to Ruptly TV, the man was detained by Vatican gendarmerie before later being admitted to a psychiatric ward in Rome's Santo Spirito hospital.
Reports from Italy suggest he entered the church fully dressed, before stripping his clothes off in a quiet corner and proceeding to walk around naked.