Members allegedly belonging to the group Anonymous took down many Vatican websites on Wednesday.
The group said it was protesting child abuse scandals, corruption and what it termed as the anachronistic concepts of the Roman Catholic Church.
The official website of the Vatican, www.vatican.va, remained inaccessible for quite some time.
The ‘hacktivists’ were quoted by the Agence France Presse as saying that Anonymous decided to besiege Vatican site in response to the doctrine, to the liturgies, to the absurd and anachronistic concepts that the church spreads around the world.
"This attack is not against the Christian religion or the faithful around the world but against the corrupt Roman Apostolic Church," the members added.
They also accused the Catholic Church of misconducts including harbouring Nazi war criminals and allowing its representatives to harass children.
Anonymous group uses a distributed denial-of-service (DDoS) attacks, in which many computers are simultaneously made to visit a website until its servers are overloaded.
In January, Anonymous temporarily knocked off the websites of the US DOJ and the Federal Bureau of Investigation in retaliation to the shutdown of the Megaupload file sharing website.
