Holocaust survivors have demanded Poland's president Andrzej Duda explain why artists were allowed to film a naked game of tag inside a gas chamber at the former Nazi death camp of Stutthof.
The video, entitled "The Game of Tag", shows a group of about eight adult men and women running in the nude around the gas chamber as they try to tag one another.
Some are seen laughing and joking as they dart furiously around the bleak concrete and brick room, which is still stained yellow from the Cyclone B gas used to kill prisoners. Others appear more serious.
The film, by Polish artist Artur Zmijewski, also shows the nude group playing the childhood game in another dingy room.
The piece ends with the text: "The film was shot in two different locations: in the basement of a private home and in a gas chamber of one of the former concentration camps."
The film was made in 1999 and has long attracted controversy. It was pulled from a 2015 exhibition in Krakow following protests from Jewish groups, who branded it insensitive, before later being reinstated by curators after defending the piece under freedom of artistic expression.
But on Wednesday (29 November), the Center Organization of Holocaust Survivors in Israel, the Simon Wiesenthal Center and several other Jewish groups sent a letter to Duda and the Polish authorities demanding fresh answers after new research suggested the piece was filmed at Stutthof concentration camp.
The camp was built by the Germans in 1939 in a secluded area near the town of Sztutowo, about 50km (31 miles) from the port city of Gdansk, and housed 110,000 men, women and children during World War Two.
About 65,000 prisoners died in the camp, with many murdered in the gas chambers.
The signatories of the letter demanded to know whether the artists did "obtain permission from the Stutthof administrators to make this video, what rules exist for proper conduct at the site, how these are enforced", the Times of Israel reported.
It also asked whether an investigation of the circumstances of the making of the video had been carried out.
Efraim Zuroff, the Wiesenthal Center's chief 'Nazi hunter', said in 2015 about the film: "It is the most disgusting thing I've seen in a long time ... It is just revolting and a total insult to the victims and anyone with any sense of morality or integrity."
But filmmaker Zmijewski – once ranked by Newsweek as one of the 10 most important artists in the world – has defended his work.
"Berek [Game of Tag] is about a part of history that is treated as 'untouchable' and about overly painful memories, when the official commemorations of this history are not enough," he wrote of his piece.
"The murdered people are victims – but we, the living, are also victims. And as such we need a kind of treatment or therapy, so we can create a symbolic alternative; instead of dead bodies we can see laughter and life.
"Berek is about how we can engage with this brutal history and work with imposed memory. It's possible to have active access to history, and to attempt to emancipate ourselves from the trauma."
In response to attempts to have his work banned from exhibitions, he added that "acts of censorship always hurt the dignity of the living".