President Donald Trump speaks on Capitol Hill in Washington, April 25, 2017, during the United States Holocaust Memorial Museum's National Days of Remembrance ceremony.
President Donald Trump speaks on Capitol Hill in Washington, April 25, 2017, during the United States Holocaust Memorial Museum's National Days of Remembrance ceremony.

WASHINGTON - U.S. President Donald Trump vowed Tuesday to confront anti-Semitism and hatred as he commemorated Holocaust Remembrance Day in a ceremony at the U.S. Capitol.

“We will stamp out prejudice, we will condemn hatred, we will bear witness and we will act,” Trump said. “As president of the United States, I will always stand with the Jewish people and I will always stand with our great friend and partner, the state of Israel.”

He said, “Those who deny the Holocaust are an accomplice to this horrible evil and we'll never be silent. We just won't. We will never, ever, ever be silent in the face of evil again.”

He called Nazi German leader Adolf Hitler's annihilation of 6 million Jews in World War II “history's darkest hour,” and condemned those who deny the Holocaust.

WATCH: Trump on confronting anti-semitism

“Denying the Holocaust is only one of many forms of dangerous anti-Semitism that continues all around the world,” he said. “We've seen anti-Semitism on university campuses, in the public square and in threats against Jewish citizens. Even worse, it's been on display in the most sinister manner when terrorists attack Jewish communities or when aggressors threaten Israel with total and complete destruction. This is my pledge to you  we will confront anti-Semitism.”

“That is why we are here today,” Trump told the audience, “to remember and to bear witness. To make sure that humanity never ever forgets.”

In his speech, Trump did not identify the “aggressors” threatening to destroy Israel or the Holocaust deniers whom he called an “accomplice” to the genocide. But that did not bother David Menashri, an Israeli professor of Middle Eastern history at Tel Aviv University.

“I’m glad that the president did not mention any specific 'address' (in terms of who is being an aggressor toward Israel or accomplice to the Holocaust) and that he left it to people to think about what he had in mind and to whom he was referring,” Menashri told VOA's Persian Service in an interview.

Menashri said there are many sources of Holocaust denial in the international arena. “Holocaust denial is a European phenomenon that also infiltrated the Middle East, with Holocaust denial conferences having been held in Iran and in other places,” he said. “But if you are looking for a connection to the Middle East (in Trump's speech), one remark that may relate only to Iran is his reference to those who call for total and complete destruction of Israel, there is only one state (that does so), and this is Iran.”

Trump's pledge to “confront” anti-Semitism also could take several forms, according to Menashri. “There are many ways to confront people without starting a war over these issues,” he said. “You can sit and speak with people in different places and have them listen to and look at the material and evidence (of the Holocaust), because denying the Holocaust is basically like paving the way for another Holocaust, and this is something that the free world would not be able to tolerate.”

WATCH: Trump vows to stand behind Jewish people, Israel

Trump's speech commemorating the carnage of seven decades ago comes after some American Jewish groups and other critics of the president denounced two White House comments related to the Holocaust in the first three months of his White House tenure.

In January, shortly after taking office, he issued a statement on International Holocaust Remembrance Day honoring “the victims, survivors, heroes of the Holocaust” without mentioning the Jews who accounted for the majority of those victims.

Earlier this month, White House spokesman Sean Spicer issued an apology after using a press briefing to say “someone who was as despicable as Hitler … didn't even sink to using chemical weapons.” Spicer made the remark as he compared the Nazi leader with Syrian President Bashar al-Assad, whom the Trump administration accused of carrying out a sarin gas attack on Syrian civilians on April 4. Hitler did not use chemical weapons on the battlefield, but he did use gas chambers to exterminate Jews, disabled people and others.

Michael Lipin of VOA's Persian Service contributed to this report.