(Adds details of attack)
ROME, Jan 24 (Reuters) - A small makeshift explosive device blew up in a street in central Rome in the early hours of Friday, causing slight damage to a building belonging to a French religious establishment and three parked cars, police said.
There was no immediate word on what was behind the explosion, which occurred hours before a visit to Pope Francis by French President Francois Hollande but security was tight near the Vatican ahead of the meeting.
According to a tweet from the French embassy to the Vatican, the church of Saint-Yves des Bretons, part of a religious foundation known as Les pieux etablissements de la France, is located in the street. (Reporting by Roberto Landucci; Editing by Jon Boyle)