Ceremonies were being held Monday in Germany and Poland in remembrance of the victims of the Third Reich, with a Russian Holocaust survivor to address the German Parliament.
Russian author Daniil Granin, 95, who was transported to Auschwitz in 1944 after surviving the Nazi siege of what was then Leningrad, was the keynote speaker in the Bundestag.
Observances in parliament are already underway, with German President Joachim Gauck leading the country's lawmakers in a moment of silence to honor the victims of Nazism.
Monday's commemorations for International Holocaust Remembrance Day come 69 years after Soviet soldiers swept into former death camp Auschwitz in Nazi-occupied Poland to liberate about 7,000 surviving inmates.
In addition to the 6 million Jews who were murdered by the Nazis, International Holocaust Remembrance Day also commemorates other victims of the Third Reich, including the mentally ill, homosexuals and Roma and Sinti.
"We honor every one of those brutally murdered in the darkest period of European history," said EU Foreign Policy Chief Catherine Ashton.
"It is an occasion to remind us all of the need to continue fighting prejudice and racism in our own time."
Separately, more than 60 Israeli lawmakers - over half the members of the Knesset - are set to join Holocaust survivors at Auschwitz to honor more than 1 million people who died there during World War II.
"The symbolism could not be any more striking - mere meters away from the gas chambers where millions of Jews were once murdered, will meet the representatives of the parliament of the Jewish State of Israel," said Jonny Daniels, executive director of From the Depths, the Jewish non-governmental organization spearheading the initiative.
Most of those killed at what was Germany's biggest death camp were Jews who were transported there from across Nazi-occupied Europe.
Survivors are expected to lay flowers at Auschwitz's death wall, where thousands of inmates were shot.
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