OSWIECIM, Poland (REUTERS) - Auschwitz's last survivors urged the world not to forget the horror of the Holocaust 70 years after the Nazi death camp was liberated in the final throes of World War Two, an anniversary that finds Europe again confronted by intolerance.
European Jews warn of a growing under-current of anti-Semitism, fuelled by anger at Israeli policy in the Middle East and social tensions over immigration, inequality and increasing economic hardship under austerity policies that have contributed to a rise of far-right political movements in Europe.
With deep snow blanketing the Polish countryside, some 300 aging survivors and a host of world leaders gathered on Tuesday under a tent at the brickwork entrance to the Auschwitz II-Birkenau camp, the railway tracks that bore more than a million European Jews to their deaths illuminated in gold.
"Seventy years later, the daily cruelty is still etched in my mind," former prisoner Roman Kent told the gathering.
The commemoration marked perhaps the last major anniversary that survivors of Auschwitz, the youngest of them in their 70s, will be able to attend in notable numbers.
It was held in the shadow of war in neighbouring Ukraine, a spate of assaults on Jews in Europe and a recrudescence of open anti-Semitism even as memories of the Holocaust fade with the passing of those who lived through it.
"To remember is not enough; deeds are crucial," said Kent."It is our mutual obligation - the survivors and world leaders - to install an understanding of what happens when prejudice and hatred are allowed to flourish."
A string quartet played the work of Szymon Laks, a Polish Jewish composer who led the prisoners' orchestra of Auschwitz-Birkenau and managed to survive the war. David Wisnia, an 88-year-old survivor of Auschwitz, sang a funeral prayer of the Ashkenazi Jews, moving some of those present to tears.
Seated among them were the heads of state of Germany, France and other nations. France's Francois Hollande made the trip less than three weeks after 17 people, four of them Jews, were killed in Paris by Islamist gunmen in attacks on the Charlie Hebdo satirical weekly newspaper and a kosher supermarket.
Speaking earlier in the day at the Paris Shoah memorial, Hollande addressed France's 550,000-strong Jewish community: "You, French people of the Jewish faith, your place is here, in your home. France is your country."
Around 1.5 million people, mainly European Jews, were gassed, shot, hanged and burned at the Nazi German death camp in southern Poland, before the Soviet Red Army entered its gates in the winter of 1945 during its decisive advance on Berlin.
Auschwitz has become probably the most poignant symbol of a Holocaust that claimed six million Jewish lives across Europe.
Chancellor Angela Merkel said Germans had an everlasting responsibility to fight all forms of anti-Semitism and racism.
"We've got to expose those who promote prejudices and conjure up bogeymen, the old ones as well as the new," Merkel said on the eve of the anniversary, in apparent reference to the right-wing grassroots PEGIDA movement in Germany.
The camp's victims included, among others, Roma, homosexuals and all shades of political opposition to the Nazis.
Notable for his absence was Russian President Vladimir Putin, whose support of pro-Russian separatist rebels in Ukraine has helped drive Western-Russian relations to their lowest ebb since the Cold War ended 25 years ago.
Poland has been one of the most vociferous critics of Russia's March 2014 annexation of Ukraine's Crimean peninsula and its support for Russian-speaking rebels in eastern Ukraine.
Keen to avoid a domestic political furore, Poland did not send a full diplomatic invitation to Putin, sources told Reuters.
"It would be hard to imagine, in this situation, hosting Russia's president. Albeit informally, Russia is taking part in this (Ukraine) conflict," Polish Justice Minister Cezary Grabarcyk told Polish ZET radio.
NATO says Russia has sent men and armour to aid the separatists. Putin denies this, but risks new sanctions when European Union foreign ministers meet on Thursday.
Among those who made the return trip to Auschwitz for the first time on Tuesday was 84-year-old Susan Pollack, who made Britain her home after the war having lost her mother to the camp's gas chambers.
Pollack said: "If at all possible, I'm hoping maybe some relief will come. And I want cry it out, because back then crying in the camp meant weakness, and weakness meant death."