Oswiecim, Poland - Elderly Holocaust survivors wearing striped scarves that recalled their uniforms as prisoners of Nazi Germany made a yearly pilgrimage to Auschwitz on Saturday, exactly 73 years after the Soviet army liberated the death camp in occupied Poland.

On the date now commemorated as International Holocaust Remembrance Day, political leaders and Jewish officials warned that the Nazi genocide must never cease serving as a reminder of the evil of which humans are capable.

In Warsaw, Poland, U.S. Secretary of State Rex Tillerson attended a solemn ceremony at a memorial to the Jews who died fighting the German forces in the Warsaw Ghetto Uprising of 1943.

Tillerson trailed two uniformed Polish military officers and readjusted a wreath underneath the monument, a hulking structure located in what was once the Warsaw Ghetto.

The head of Warsaw’s Jewish community read a prayer, and Tillerson made brief remarks about the importance of not forgetting the horrors of the Holocaust.

“On this occasion, it reminds us that we can never, we can never, be indifferent to the face of evil,” Tillerson said.

“The Western alliance which emerged from World War II has committed itself to ensuring the security of all that this would never happen again,” he said. “As we mark this day in solemn remembrance, let us repeat the words of our own commitment: Never again. Never again.”

His words came amid signs in Europe and beyond that ultranationalism and extreme right-wing groups are on the rise.

In Germany and Austria, the nations that perpetrated the killing of 6 million Jews and millions of others during World War II, far-right parties with their roots in the Nazi era are gaining strength.