President Trump and his family laid a wreath at Yad Vashem, Israel's Holocaust memorial, as they wrapped up their visit to Jerusalem on Tuesday.
"It was the most savage crime against God and his children," Trump said Tuesday of the Holocaust, which he called "history's darkest hour."
Israeli Prime Minister Benjamin Netanyahu accompanied Trump, his wife Melania, his daughter Ivanka and her husband, Jared Kushner.
Trump said the nation of Israel "is a strong and soaring monument to the solemn pledge we repeat and affirm: never again."
"Words can never describe the bottomless depths of that evil or the scope of the anguish and destruction," the president added.
Trump was invited to rekindle the Eternal Flame at the Holocaust memorial site. The flame burns continuously in the Hall of Remembrance, where a stone crypt holds the ashes of Holocaust victims.
After Netanyahu thanked the president for the visit, he commented briefly on Trump's remarks earlier Tuesday in which he'd called the terrorists who attacked a British concert hall on Monday "evil losers."
"It's our job to make sure that they continue to lose," Netanyahu said.
Trump's visit to Yad Vashem marked one of the final stops on his trip to the Middle East. Later Tuesday, he will depart Tel Aviv for Rome as he continues on his five-country international debut.