A French museum has re-opened with boosted security measures following a weekend protest against and attack on the controversial artwork Immersion (Piss Christ).

Avignon's Lambert Collection Museum of Contemporary Art re-opened its doors on Tuesday for the first time since a vandal attacked Andres Serrano's controversial work — a photo of a plastic crucifix submerged in his urine — on display at the southern French art venue on Sunday.

Extra staffers have been posted at the entrance to aid in checking bags, while plainclothes officers are reportedly circulating inside the museum.

Officials decided to leave Immersion and The Church (Sister Jeanne Myriam) — another Serrano work marred by Sunday's act of vandalism — on display so the public can view the damage.

The museum shuttered on Monday for its weekly closing, but police spent the day questioning witnesses.

Religious protests 

According to witnesses, museum staff stopped a pair who tried to smuggle a can of spray paint and a chisel into the museum late Sunday morning.

While staffers were distracted, a third individual entered and smashed Serrano's artwork with a hammer. Guards attempted to stop the man, who also damaged The Church (Sister Jeanne Myriam) — a close-up image of a nun's hands — during the struggle. With the help of an accomplice, the vandal managed to escape.

The Lambert exhibit featuring Immersion has been on display since December and continues on until May.

Earlier this month, the Catholic bishop of Avignon singled out Serrano's contentious 1976 artwork and called for its removal from the gallery. On Saturday, hundreds of people gathered outside the museum to protest the work.

French Culture Minister Frédéric Mitterrand has said he recognized that the image was shocking to some people, but he also condemned Sunday's vandalism as "an attack on a basic principle: the exhibition of these works being fully in line with the freedom of creation and expression enshrined in law."

Serrano first sparked controversy with Immersion when it won a U.S. art prize in 1987 and was subsequently blasted by conservative critics. The New York-based artist has described Immersion as a condemnation of the "billion-dollar Christ-for-profit industry."

Calling himself a "Christian artist," he told France's Libération newspaper this week he was shocked by the reaction to his work.

With files from The Associated Press