A Roman art gallery that was threatened with legal action by the Vatican over a photo installation depicting gay kisses inside churches has been attacked by vandals.

A group of spray-can-wielding thugs defaced several paintings at L'Opera art gallery in central Rome.

"The attack aimed to censor the exposed art works; to hurt the works of the artists and the values they represent," the gallery said.

Gallery assistant Martina Adami told IBTimes UK that five Italian men in their early 20s raided the premises as the gallery was open at 7pm local time, before running off.

"As one approached me asking information about the exhibition, the others rushed in and spray painted three works," Adami said, adding they wore hoodies but also sported some designer clothing, suggesting they were of good upbringing.

The attackers vandalised three paintings by artists Mauro Maugliani, Gonzalo Orquín and Luis Serrano worth an estimated total of €36,000 (£30,000).

The worst affected work was In God We Trust by Maugliani, which depicts a young woman dressed as a Catholic priest.

"It was deemed offensive to religion," Adami, who was the only staff at the gallery when it was attacked, said. "[The painting] raises questions about women's role in the church."

The Holy See doesn't allow women to be ordained priest.

Adami said renovation works will hardly bring back the scarred paintings that have, however, been left exposed to show the artists' struggle against censorship and violence in Italy.

The three works are part of an exhibition titled Trialogo, which includes a piece by Orquín that had raised the ire of the Vatican.

Si, Quiero, [Spanish for 'Yes I Do'] an installation of 16 shots depicting same-sex couples kissing in front of the altar of different churches, had to be covered up after the Vicariate of Rome threatened to sue the art gallery.

The Vicariate said that the shots were taken without its authorisation and showed "love expressions not suitable for a holy place and thus harmful to the religious sentiment of the faithful."

As the controversial photos were published by Italian media, some netizens vowed to destroy the art work while commenting on a catholic blog that described the exhibition as an "unacceptable provocation by the enemies of the Church".

The artist decided to leave the installation up but covered it up with a black board matched with some black crosses to represent grief.

Si, Quiero was left untouched by the vandals. Police are investigating the incident.

gay kiss art
Si, Quiero by artist Gonzalo Orquín (Facebook)
gay kiss church vatican censorship
Si, Quiero by artist Gonzalo Orquín, after it was covered up following a threat of legal action by the Vatican (Facebook)