Police in the south of France on Monday sought two vandals who destroyed a US artist's photograph of a plastic crucifix submerged in urine that outraged American conservatives in the 1980s. Two men armed with a hammer and a screwdriver-like device attacked "Piss Christ" by New York-based Andres Serrano at the Collection Lambert museum of contemporary art in Avignon on Sunday, officials said. A second Serrano photograph, "The Church: Sister Jeanne Myriam," was also targeted in the late-morning incident in which three guards who tried to intervene were assaulted, the museum's founder Yvon Lambert said. Closed on Mondays, the museum -- which spotlights "Piss Christ" on the homepage of its website (www.collectionlambert.com) -- intends to reopen its doors on Tuesday "with the damaged works shown as they are". Several hundred conservative Christians had demonstrated outside the gallery on Saturday, while the Roman Catholic bishop of Avignon, Jean-Pierre Cattenoz, had called for the "odious" photograph to be removed. French Culture Minister Frederic Mitterrand condemned "an attack on a basic principle, the exhibition of these works being fully in line with the freedom of creation and expression enshrined in the law." He admitted however that "one of the two works could shock some people." "Piss Christ" triggered an uproar in 1987 after it won its creator -- who claimed the urine was his -- a prize underwritten by the National Endowment of the Arts, which gets taxpayer support through the US government. The late conservative senator Jesse Helms led a political charge against it, holding it up as an example of publicly-funded "slime and sleaze" in the world of contemporary art. Serrano made 10 Cibachrome prints of "Piss Christ", including one that sold at a Christie's auction in New York for a higher-than-expected 277,000 dollars in May 2008, and an equal number of "Sister Jeanne Myriam".