(AP) — US President Donald Trump on Monday stressed the importance of remembering lessons of the Holocaust, underscoring the need to “remain vigilant against hateful ideologies and indifference.”

“Every generation must learn and apply the lessons of the Holocaust so that such horror, atrocity, and genocide never again occur,” Trump said in a proclamation marking the Days of Remembrance of the Victims of the Holocaust.

Recalling that the Holocaust was “the state-sponsored, systematic persecution and attempted annihilation of European Jewry by the Nazi regime and its collaborators,” the Republican president stressed the need to “remember the victims, honor their memory and their lives, and celebrate humanity’s victory over tyranny and evil.”

“We pledge to never be bystanders to evil. We must never forget,” said Trump, who will give a speech Tuesday at the US Holocaust Memorial Museum in Washington.

Secretary of State Rex Tillerson said in a statement the world was “blessed that Holocaust survivors continue to inspire us with their first-hand experiences and to steel our resolve to combat anti-Semitism and all forms of hatred.”

Presidential adviser and first daughter Ivanka Trump, who converted to Judaism before marrying Jared Kushner, said in a White House statement that world leaders should pledge to ensure that “genocide like the Holocaust will never happen again.”

She will be in Berlin on Tuesday participating in a “Women 20” meeting about female economic empowerment, and will visit the Memorial to the Murdered Jews of Europe, the statement said.

President Trump raised eyebrows in January shortly after taking office when he issued a statement marking Holocaust Remembrance Day that made no mention of the six million Jews killed.

The Anti-Defamation League, which tracks acts of anti-Semitism, called the omission “puzzling and troubling.”

Trump was also criticized for his slow reaction to a spate of anti-Semitic threats against Jewish community centers.

Earlier this month, White House spokesman Sean Spicer was forced to apologize after appearing to favorably compare Adolf Hitler’s actions during the Holocaust to atrocities carried out now by Syrian strongman Bashar al-Assad.

His comments provoked outrage far beyond America’s borders, especially in Israel.