In ceremonies marking the end of World War II, Austria's president Heinz Fischer has urged fellow Austrians to face the truth about the Hitler era, alluding to recent pro-Nazi comments by some politicians, including one who questioned the existence of gas chambers. Fischer spoke at Hartheim Castle, where almost 30,000 people were gassed or given fatal injections because they did not meet the Nazis' pseudo-Aryan ideals. "There is nothing to put in context, to try and paper over and ... nothing that still needs to be researched," Fischer said, referring to recent suggestions that horrors perpetrated by the Nazis were open to debate. While Fischer named nobody in particular, his comments were clearly a response to suggestions by lawmaker John Gudenus that the existence of Nazi gas chambers still needed to be investigated. Gudenus, a member of Austria's largely powerless upper house, is under review by the Vienna prosecutor's office to see whether he violated a law prohibiting people from trying to diminish, deny or justify the Holocaust in public. A conviction carries a penalty of up to 10 years in prison.