(JNS.org) More than 300 Holocaust survivors along with world leaders gathered at the site of the Auschwitz-Birkenau concentration camp on Tuesday to commemorate the 1.1 million people killed there, as well as the millions of other victims killed during the Holocaust, as part of International Holocaust Remembrance Day.

Halina Birenbaum, an 85-year-old Polish-Jewish survivor of the camp, said at the ceremony that Auschwitz was “like nothing similar to anything in human experience.”

“Cursing, beatings, sophisticated torture, corporal punishment for petty offenses or for nothing at all. Columns of people being led to gas chambers. A pillar of fire straight to the sky. Trains and trains full of new victims,” she said, the Wall Street Journal reported.

In a speech, president of the World Jewish Congress Ronald Lauder warned that “slowly the demonization of Jews started to come back. Once again, young Jewish boys are afraid to wear yarmulkes on the streets of Paris and Budapest and London. Once again, Jewish businesses are targeted. And once again, Jewish families are fleeing Europe.”

In addition the “vilification of Israel, the only Jewish state on earth, quickly became an opportunity to attack Jews. Much of this came from the Middle East, but it has found fertile ground throughout the world,” Lauder added, the Associated Press reported.

In an official statement, President Barack Obama, who was not present at the ceremony, said that “the recent terrorist attacks in Paris serve as a painful reminder of our obligation to condemn and combat rising anti-Semitism in all its forms, including the denial or trivialization of the Holocaust.”

Numerous global leaders attended the commemoration of Auschwitz’s liberation from Poland, France, Germany, and several other European countries. Absent from the commemoration was also Russian President Vladimir Putin. Russian Chief of Staff Sergei Ivanov attended the event instead, as did U.S. Treasury Secretary Jack Lew, who is Jewish.

Putin was present at a separate Holocaust commemoration at Moscow’s Jewish Museum and Center for Tolerance on Tuesday.

At a reception in Krakow with 100 Auschwitz survivors on the eve of the gathering on Monday, American-Jewish film director Steven Spielberg—director of the famed Holocaust motion picture “Schindler’s List”— also said “we need to be preserving places like Auschwitz so people can see for themselves how evil ideologies can become tangible acts of murder.”