A far-right Greek lawmaker attacked four paintings in an exhibition at the country's National Gallery on Monday, the gallery said, after he had described one as offensive because of its distorted depictions of Christ and the Virgin Mary.

The lawmaker, named by the gallery as Nikolaos Papadopoulos, from the ultra-religious Niki party, was temporarily detained, and the gallery said it had had to close for the day due to the incident.

The gallery said that with assistance from another person he had violently taken down four paintings included in the exhibition inspired by Spanish master Francisco de Goya.

"The above violently detached them from the wall and threw them on the floor, which resulted in their damage," the gallery said in a statement.

Papadopoulos' lawyer Constantinos Vathiotis told Reuters that he was illegally detained for five hours. Lawmakers are protected from arrest under the constitution and only parliament can lift their immunity.

The exhibition, "The allure of the bizarre," is by a group of Greek artists, with works corresponding with 80 etchings from Goya's late 18th century Los Caprichos series. It has been on display in Athens since January at the country's main gallery, which is a major draw for Greeks and tourists alike.

In a question to the culture ministry submitted to parliament in January, the lawmaker said that one painting, among the group of four he is accused of damaging, was "clearly offending the Orthodox Christian faith, directly insulting the holy faces of Virgin Mary and Christ, which are depicted distorted."

The culture ministry responded at the time that it "never engages in censorship."

The Hellenic League for Human Rights condemned the lawmaker's action, saying "freedom of art and freedom of expression are protected by the constitution and are not subject to the personal taste and religious and ideological beliefs of self-appointed judges and ultimately punishers."