WARSAW, Poland -- Jewish and Christian leaders prayed over the ruins of gas chambers at Auschwitz-Birkenau as some warned on International Holocaust Remembrance Day of rising xenophobic hatred against Jews, Muslims and others.

Camp survivors gathered Friday with political leaders and representatives of Poland’s Jewish community at the site where Germany murdered about 1.1 million people during World War II, mostly Jews from across Europe, but also Poles, Roma, Soviet prisoners of war and others.

Poland’s Prime Minister Beata Szydlo, who is from the Polish town where the Auschwitz memorial and museum is located, Oswiecim, recalled the “destruction of humanity” and the “ocean of lost lives and hopes” that resulted from the German genocide.

“It’s an open wound that may close sometimes but it shall never be fully healed and it must not be forgotten,” she said.

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Dozens of Auschwitz survivors began a day of commemorations by placing wreaths and flowers at the infamous execution wall on the 72nd anniversary of the camp’s liberation by Soviet soldiers.

The United Nations recognized January 27 as International Holocaust Remembrance Day in 2005, and many commemorative events were held across the world.

“Tragically, and contrary to our resolve, anti-Semitism continues to thrive,” U.N. Secretary-General Antonio Guterres said. “We are also seeing a deeply troubling rise in extremism, xenophobia, racism and anti-Muslim hatred. Irrationality and intolerance are back.”

Newly elected United Nations Secretary-General Antonio Guterres waits to deliver remarks to the media at U.N. headquarters on Oct. 13, 2016, in New York City. Getty

Guterres vowed to “be in the front line of the battle against anti-Semitism and all other forms of hatred.”

In Germany, outgoing Foreign Minister Frank-Walter Steinmeier said his nation sticks by its obligation to take responsibility for the crimes committed by the Nazi regime of Adolf Hitler.

Noting the political instability in the world today, Steinmeier said, “History should be a lesson, warning and incentive all at the same time. There can and should be no end to remembrance.”

In Albania’s capital, Tirana, an olive tree was planted during the inauguration of a downtown garden commemorating Albanians who saved Jews during the war.

Speaking alongside the Israeli ambassador, Foreign Minister Ditmir Bushati said Albanians are proud their predecessors handed over no Jews to the Nazis who occupied Albania from 1943-44.

Albania was the only country in Europe where the number of the Jews during World War II increased after the Muslim majority population provided refuge to Jews fleeing other countries.

On Friday, rising far-right sentiments cast a shadow on some remembrance day events, including in Germany.

The Buchenwald concentration camp memorial rescinded an invitation to a prominent member of a nationalist party who suggested that Germany should stop atoning for its Nazi past.

Bjoern Hoecke, the leader of Alternative for Germany in the state of Thuringia, last week called Berlin’s Holocaust memorial a “monument of shame” and saying Germany should take a “positive” attitude toward its history.

The Jewish community in Croatia boycotted official commemorations, saying the country’s conservative government is not doing enough to curb pro-Nazi sentiments. The decision was made after authorities failed to remove a plaque bearing a World War II Croatian pro-Nazi salute from the town of Jasenovac - the site of a wartime death camp where tens of thousands of Jews, Serbs and Roma perished.

Elderly survivors at Auschwitz, which today is a museum and partially preserved memorial, paid homage to those killed by wearing striped scarves to symbolize the uniforms prisoners were given when they arrived at the concentration camp.

They walked slowly beneath the notorious gate with the words “Arbeit Macht Frei” (Work Will Set You Free) and made their way as a group to the execution wall, where they lit candles and prayed. The commemorations then moved to the site of Birkenau, the satellite camp some two miles away.

Janina Malec, a Polish survivor whose parents were killed at the execution wall, described her yearly visit as a “pilgrimage” and told the PAP news agency that “as long as I live I will come here.”