A man with mental health issues broke the security barrier around St Peter's Square, ramming his car through a police checkpoint and demanding to be given an audience by Pope Francis, according to police and media reports.
Rome police said in two statements that they arrested a 64-year-old "mentally unstable" Italian who drove into a one-way street to the left of St Peter's colonnade, crashed past a police vehicle and broke through the wooden barricades that surround the square.
The incident, in which nobody was hurt, took place at around 9:30 pm (1930 GMT) Friday. The intruder was described as a carpenter from Ronciglione, a town about 70 kilometers north of the Vatican, who is undergoing psychiatric treatment.
Officers acted "appropriately and correctly" in deciding not to use firearms, because they were informed that they were not dealing with a terrorist, and because the man posed "no immediate danger" to others, police stressed.
Rome-based daily Il Messaggero added that the man got out of his car and, visibly agitated, started ranting. One of the things he said was, "I want to see the pope."
Security around the Vatican and other major landmarks in Rome has recently been stepped up due to fear of terrorist attacks. The city's police force said what happened Friday should prompt "further thinking" about the security of sensitive sites.