Updated at 7:13 p.m. | House Minority Leader Nancy Pelosi is calling on President Donald Trump to fire his press secretary Sean Spicer for remarks he made Tuesday that suggested Adolf Hitler did not use chemical weapons during World War II.

Spicer was responding to a question during the daily White House briefing about Russia’s relationship to Bashar Assad’s Syrian regime and the support it has gotten from President Vladimir Putin.

American officials have said Assad killed dozens of his own people using chemical weapons. In response, Trump ordered a Tomahawk missile strike on a Syrian air base on Thursday, which could create complications with the Kremlin.

“We didn’t use chemical weapons in World War II. You know, you had someone as despicable as Hitler who didn’t even sink to using chemical weapons,” Spicer said.

Later, a reporter asked him to clarify.

“I think when you come to sarin gas, he was not using the gas on his own people the same way that Assad is doing,” Spicer said.

But Hitler did use chemical agents on some of his own people: German Jews.

“The Nazi regime brought an industrial approach to mass murder of its citizens and others it sought to exterminate,” the non-partisan fact checking organization Polifact wrote Tuesday afternoon. “The construction of gas chambers and the use of deadly gas was fundamental to that strategy.”

Pelosi noted in a statement that Spicer was “downplaying the horror of the Holocaust” during the Jewish holiday of Passover.

“Sean Spicer must be fired, and the president must immediately disavow his spokesman’s statements,” Pelosi said. “Either he is speaking for the president, or the president should have known better than to hire him.”

As Spicer struggled to explain his comments, he later walked back the remarks when he referred to Nazi death camps where Hitler’s regime killed thousands of European Jews using deadly gases.

“He brought them into the Holocaust centers, and I understand that,” Spicer said.

The Holocaust Memorial Museum cites on one of its fact sheets:

“Six gassing installations were established as part of the Euthanasia Program: Bernburg, Brandenburg, Grafeneck, Hadamar, Hartheim, and Sonnenstein. These killing centers used pure, chemically manufactured carbon monoxide gas.”

Spicer continued, stammering as he attempted to correct a massive misstep from which he is catching major blowback. He appeared to assert that aircraft-administered chemical gas attacks are worse than ones delivered in shower rooms.

“But I was saying in the way that Assad used them, where he went into towns, dropped them down to innocent — into the middle of town,” a clearly flummoxed White House Press secretary said. “It was brought — so, the use of it — and I appreciate the clarification. That was not the intent.”

In a statement made just after the briefing ended, Spicer defended his remarks.

“In no way was I trying to lessen the horrendous nature of the Holocaust,” Spicer said. “I was trying to draw a distinction of the tactic of using airplanes to drop chemical weapons on population centers.”

On Tuesday evening, Spicer spoke with several cable news networks about the gaffe, saying it was a “mistake” to use refer to Hitler. He said he is “sorry” for doing so.

Asked on MSNBC about Pelosi calling for his firing, Spicer said only that everyone makes mistakes and asks for forgiveness.

In addition to Pelosi, other Democratic members of Congress also weighed in with their own criticism.

Sen. Ben Cardin said in a tweet someone ought to give Spicer “a refresher history course on Hitler stat.”

Sen. Brian Schatz said he could “find nothing funny about the Press Secretary bungling holocaust history.”

“Because I’m not sure they should get the benefit of the doubt,” the Hawaii Democrat tweeted.

Rep. David Cilline said the White House should not get the benefit of doubt and that Spicer now joined a handful of administration officials who he believed were linked to anti-Semitism.

“Sean Spicer made despicable, ignorant remarks about the Holocaust and Adolf Hitler,” the Rhode Island Democrat said in a statement. “Enough is enough.”

John Bennett and Bridget Bowman contributed to this report.Contact Rahman at remarahman@cqrollcall.com or follow her on Twitter at @remawriter.