The leader of the World Jewish Congress has warned of a rise in anti-Semitism on the 70th anniversary of the liberation of the Nazi death camp at Auschwitz, Poland.
Ronald Lauder told hundreds of Auschwitz survivors and dozens of government officials from around the world that many thought "the hatred of Jews had been eradicated" but that "once again Jewish families are fleeing Europe" because of fear from attacks.
French President Francois Hollande, German President Joachim Gauck, and Ukrainian President Petro Poroshenko were among many government officials from dozens of countries attending the ceremonies, including royal representatives from the Netherlands and Belgium.
Poroshenko said he called "on the entire world not to allow a replay" of the Holocaust or World War II.
He said the "threat of a continental war is greater now than it has been" since World War II and added, in a reference to the conflict in eastern Ukraine, that "the aggressor's ambitions and appetites exceed Ukraine's size."
Hollande pledged earlier on January 27 to combat the "unbearable" rising anti-Semitism in France, after figures showed anti-Jewish actions doubled over the past year.
European Jewish Congress chief Moshe Kantor warned that Europe is near a new exodus of Jews and that "jihadism is very close to Nazism."
But he suggested that Jews should not be in a rush to leave Europe, and that he and others are working on legislation and other proposals to counteract "the threats of radical Islam, neo-Nazism and anti-Semitism in Europe."
Holocaust survivor Roman Kent, 85, was very emotional as he told those assembled at the ceremony that "we do not want our past to be our children's future."
U.S. President Barack Obama said in a statement that he pledged "never to forget" those murdered by the Nazi regime and also raised his concern over a rise in anti-Semitism.
On January 26, German Chancellor Angela Merkel told a group of Holocaust survivors it was a "disgrace" that Jews in Germany faced insults, threats, or violence.
Speaking in Berlin, she called Auschwitz a "warning" of what people can do to each other and said the fact that synagogues and Jewish institutions had to be guarded by police was like a "stain on our country."
January 27 is marked as International Holocaust Remembrance Day, and Auschwitz is one of the most indelible symbols of the genocide by Nazi Germany in which approximately 6 million Jews were killed. Many members of other minority groups including Roma, homosexuals, and the mentally ill were also murdered.
Soviet Army soldiers sweeping westward after Hitler's forces were beaten back from the Soviet Union freed the prisoners of Auschwitz on January 27, 1945.
The anniversary has aggravated ties between Russia and the West -- already at a post-Cold War low over the conflict in Ukraine -- with Russia venting anger over suggestions by Polish and Ukrainian officials that the camp was liberated mainly by Ukrainians.
While it is recorded that soldiers from the divisions referred to as the Ukrainian Front were involved in liberating Auschwitz, the force was comprised of many nationalities.
That row added to tension after Russian President Vladimir Putin announced through a spokesman that he would not attend the January 27 ceremony.
In what some media outlets have portrayed as a backhanded move by Poland to prevent Putin from attending the ceremony, the Auschwitz-Birkenau State Museum did not send invitations to any heads of state this year, instead notifying world leaders of the event and asking who would attend.
Russia was represented by Kremlin chief of staff Sergei Ivanov, who also warned of neo-Nazism in Europe.
He warned of its growth as an "alarming trend" and said in some European countries "the situation looks similar to the 1930s."
In Moscow, Putin marked the anniversary at the Jewish Museum and Tolerance Center, lashing out at what he called attempts to rewrite history, singling out what he said were "collaborationists, accomplices of Hitler" he said helped Nazi Germany kill Jews in Ukraine and the Baltics.
The remarks were politically charged at a time when Moscow is backing separatists fighting in eastern Ukraine against the forces of a government that Russian officials have branded as fascists.
Putin said Nazi crimes "cannot be forgiven or forgotten" and added, "any attempts to silence those events, to distort, to rewrite the history, are impermissible and immoral."
He added that "very often such attempts are driven by a desire to hide one's own shame, the shame of cowardice, hypocrisy, and betrayal, to justify direct or indirect collaboration with Nazis in the implementation of their criminal policy."
Putin also said: "Hitler's accomplices took part in the extermination of the Jewish nation, in the extermination of Jews in Lviv, Odesa, Kyiv, and other settlements in Ukraine. Baltic Nazis implemented ethnic cleansings in Vilnius and Riga, Kaunas and Tallinn."
Concerns about an uptick in anti-Semitism in Europe have been heightened by an attack in which an Islamist gunman seized hostages at a kosher grocery store in Paris on January 9 and killed four shoppers.
France's main Jewish group said on January 27 that the number of anti-Semitic acts registered there doubled in 2014 to 851, including 241 acts of physical violence.
With reporting by AP, AFP, Interfax, The Guardian, and Haaretz