The growing trend of antisemitic outbursts among leading Polish politicians and public figures reached new heights this week, when a close ally of the country’s deputy prime minister took to social media to denounce Jews as “animals.”

“Żydzi to nie ludzie to zwierzęta!” – “The Jews are not humans, they are animals!” – an enraged Kazimierz Plotkowski posted on Twitter on Wednesday. The tweet was later deleted, after being captured by several screenshots shared online.

Plotkowski, a successful businessman, is a co-founder and former regional leader of the Polska Razem (“Poland Together”) Party of deputy Prime Minister Jarosław Gowin, and an adviser to the Polish government on energy and mining. The party was founded by Gowin, an outspoken social conservative, in 2013 after he was dismissed from the post of Justice Minister in the previous government.

Following his Twitter outburst, Plotkowski told Polish news outlet NaTemat that he was responding to an unspecified “article” in which Poles were depicted as “pigs who robbed Jews in the ghetto.” However, his original tweet was posted after the museum at the Auschwitz concentration camp announced that it was replacing a small exhibition about a group of Poles executed by the Nazis in 1943 with another about resistance in the camp. Several influential Poles, including historian Adam Cyra, have protested that the decision demeans the suffering of Poles under the Nazis. A spokesperson for the museum told the PAP Polish news agency this week that the new exhibit would show the central role played by Polish inmates in building a resistance movement inside Auschwitz.

The virulence of Plotkowski’s response did not escape scrutiny. “It was not an ordinary comment like ‘I do not like it,'” NaTemat commented. “No, Mr. Płotkowski decided to take it in an extremely different way: ‘The Jews are not humans, they are animals!'”

The recent upsurge of antisemitism in Poland is closely connected to the passage in February of the widely-criticized IPN Act, which criminalizes public discussion of Polish collaboration with the Nazi authorities during World War II with a maximum sentence of three years in prison.