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.