“To this day there are those who insist that the Holocaust never happened, a denial of fact and truth that is baseless and ignorant and hateful,” Obama said, echoing his words in Cairo in an address that reached for what he called a “new beginning” in the relationship between the US and the Muslim world.

By visiting Buchenwald on Friday, he also underscored what he termed in Cairo America’s “unbreakable” bond with Israel. Obama has been pushing hard during this trip for a two-state solution in West Asia, and the administration has angered some in Israel by taking a tough stand against Israel’s expanding existing settlements.

In his visit to the former concentration camp, Obama said the site was the “ultimate rebuke” to those who deny or seek to minimise the Holocaust.

“These sights have not lost their horror with the passage of time... More than half a century later, our grief and our outrage over what happened have not diminished.”

The camp where 56,000 people died also bears a particular significance for Germans, embodying the contradiction of a civilised society’s descent into organised barbarism.

With his hands behind his back and a thoughtful expression on his face, Obama walked through the former concentration camp, flanked by Chancellor Angela Merkel and Elie Wiesel, a Nobel Peace Prize winner, writer and Holocaust survivor, who survived a death march from Auschwitz to Buchenwald and was at the camp when it was liberated in April 1945.

Wiesel spoke movingly about the death of his father a few months before the liberation of the camp, calling the visit “a way of coming and visit my father’s grave. But he had no grave”.

Obama claims a personal connection to the concentration camp. His great-uncle, Charles Payne, helped liberate a sub-camp of Buchenwald called Ohrdruf.

Merkel, who like Wiesel and Obama laid a long-stemmed white rose in memory of the dead, spoke of the German responsibility “to do everything possible that something like that never happens again”.

Earlier the two leaders met for talks in Dresden, where , President Obama declared that “the moment is now” to press for West Asia settlement. He put Israelis and Palestinians on notice that it was up to them to make “difficult compromises”.

The President said he was dispatching his top envoy George Mitchell to the region next week to follow up on issues raised during the Cairo speech.

“The moment is now for us to act on what we all know to be the truth, which is that each side is going to have to make some difficult compromises. We have to reject violence,” Obama said.