The Anti-Defamation League (ADL) has volunteered to offer training sessions focused on Holocaust education to White House spokesman Sean Spicer, whose comparison of Syrian President Bashar al-Assad to Adolf Hitler on Tuesday sparked an uproar.

During the daily White House press briefing, Spicer incorrectly claimed on Tuesday that Hitler didn’t use chemical weapons during World War II. He also referred to concentration camps as “Holocaust Centers.” Spicer later apologized for his gaffes.

Because it was still Passover when he made those comments, some Jews didn’t see them until they turned on their TVs and phones the following evening on Wednesday.

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“Your comparisons between Assad and Hitler were not only historically inaccurate but they also were inappropriate and offensive,” said ADL CEO Jonathan Greenblatt in a letter to Spicer Thursday.

For decades, the ADL has provided trainings about the Nazi atrocities and the Holocaust to hundreds of thousands of students, educators and law enforcement officials, Greenblatt said. He said the programs provide historical context about how the Holocaust occurred and prompt critical thinking.

“ADL would be happy to conduct one of these trainings at your convenience for you, your staff, and anyone at the White House who may need to learn more about the Holocaust,” he said. “We know you are very busy, but we believe a few hours learning this history will help you understand where you went wrong and prevent you from making these mistakes in the future.”