Pledging to confront anti-Semitism in all its forms and to "never be silent," President Donald Trump on Tuesday denounced as accomplices to "horrible evil" anyone who denies that 6 million Jews were killed during the Holocaust.

In a speech marking Holocaust Remembrance Day, Trump also pledged that as president of the United States he will "always stand with the Jewish people."

Trump spoke at a U.S. Capitol ceremony hosted by the U.S. Holocaust Memorial Museum to mark the unveiling of a new conservation and research center. The center will serve as a repository for a vast collection of artifacts by those who survived Adolf Hitler's massacre of Jews during World War II.

Members of Congress and Holocaust survivors -- whose strength and courage Trump said was an inspiration -- attended the emotional event in the Rotunda, the center of the Capitol. Survivors lit candles at the end of the ceremony.

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

Trump said Holocaust denial is one form of "dangerous anti-Semitism that continues all around the world" and that can be seen on university campuses, in attacks on Jewish communities "or when aggressors threaten Israel with total and complete destruction."

"This is my pledge to you: We will confront anti-Semitism," he said. "We will stamp out prejudice, we will condemn hatred, we will bear witness and we will act. 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."

Trump's commemoration of the Holocaust follows a recent blunder by his chief spokesman, Sean Spicer, on the issue.

Spicer recently apologized for making what he later said was an "inappropriate and insensitive" statement earlier this month that compared Hitler to Syrian President Bashar Assad by suggesting that Hitler "didn't even sink to using chemical weapons."

The remark, which Spicer had made days after a chemical attack in Syria killed scores of civilians, ignored Hitler's use of gas chambers to kill Jews.

The White House's commitment to fighting anti-Semitism was questioned earlier in the year after it released a statement on International Holocaust Remembrance Day that excluded any mention of the Jewish people, in contrast to similar statements from previous administrations.

Trump's own relations with American Jews had become strained after a testy exchange during a news conference with a reporter for an Orthodox Jewish publication. Some also thought Trump had waited too long to come out forcefully against bomb threats against Jewish community centers nationwide.

Trump's daughter, Ivanka Trump, converted to Judaism before marrying her husband, Jared Kushner, now a senior White House adviser. On an official trip Tuesday to Berlin, Ivanka Trump, now working at the White House as an assistant to the president, visited the Memorial to the Murdered Jews of Europe.

Addressing survivors in attendance at the Capitol, Trump called each one a "beacon of light."

"It only takes one light to illuminate even the darkest space, just like it takes only truth to crush a thousand lies and one hero to change the course of history," he said. "We know that in the end good will triumph over evil and that as long as we refuse to close our eyes or to silence our voices, we know that justice will ultimately prevail."