The Anne Frank Center for Mutual Respect is calling on President Trump to fire White House spokesman Sean Spicer “at once” — saying his comment about Adolf Hitler not using chemical weapons was a flat-out Holocaust denial, on Passover no less.

In a statement posted to Facebook, executive director Steven Goldstein described how he was appalled by Spicer’s press briefing on Tuesday, when he unabashedly said: “Someone who is [as] despicable as Hitler didn’t even sink to using chemical weapons.”

To make matters worse, the press secretary later referred to concentration camps as “Holocaust centers” as he tried to explain the reasoning behind his comments.

“Sean Spicer has engaged in Holocaust denial, the most offensive form of fake news imaginable, by denying Hitler gassed millions of Jews to death,” Goldstein seethed. “Spicer’s statement is the most evil slur upon a group of people we have ever heard from a White House press secretary.

“Sean Spicer now lacks the integrity to serve as White House press secretary, and President Trump must fire him at once,” he added. “#Antisemitism. #NeverAgain.”

Spicer had been explaining why he believed Syrian President Bashar al-Assad was even more evil than Hitler following last week’s chemical attack.

“You had someone as despicable as Hitler, who didn’t even sink to using chemical weapons,” Spicer said.

The German leader is notorious for his use of cyanide gas in the mass killings of Jews before and during World War II.

When a reporter asked Spicer to clarify his statement, he said: [Hitler] brought them into the holocaust center. [Not] the way Assad dropped the bombs into the middle of towns.”