NORTH LAS VEGAS, Nev. - Sen. Barack Obama's campaign said yesterday that the candidate mistakenly referred to the wrong Nazi death camp when relating the story of a great-uncle who helped liberate the camps in World War II.

It said the story was accurate except that the camp was Buchenwald, not Auschwitz.

Campaign spokesman Bill Burton said in a statement that Obama "mistakenly referred to Auschwitz instead of Buchenwald in telling of his personal experience of a soldier in his family who served heroically."

Obama's family "is proud of the service of his grandfather and uncles in World War II - especially the fact that his great-uncle was a part of liberating one of the concentration camps at Buchenwald," Burton said.

Aides said a brother of Obama's grandmother, Charlie Payne, helped liberate a Buchenwald sub-camp in April 1945 as part of the 89th Infantry Division.

During a meeting Monday with veterans, Obama discussed the importance of improving treatment for troops suffering post-traumatic stress. To illustrate his point, he talked about his own family.

"I had an uncle who was part of the first American troops to go into Auschwitz and liberate the concentration camps," Obama said. "The story in our family was that when he came home, he just went up into the attic and he didn't leave the house for six months.

"Now, obviously something had really affected him, but at that time there just weren't the kinds of facilities to help somebody work through that kind of pain."

Auschwitz was liberated by Soviet forces as they marched across Poland in January 1945. The U.S. Holocaust Memorial Museum says Americans liberated several death camps in Germany, including Buchenwald, Dachau and Mauthausen.

Obama's mistaken mention of the camp on Monday had quickly generated Internet chatter, ranging from puzzlement to outrage. The Republican Party had demanded an explanation.