Holocaust survivors gathered at Auschwitz-Birkenau on Monday to mark the 75th anniversary of the liberation of the death camp — and sound the alarm about rising anti-Semitism worldwide.

About 200 survivors, many joined by their descendants, attended the commemoration for the more than 1.1 million people, most of them Jews, killed at the Nazi camp in occupied Poland.

Several of the survivors wore blue- and white-striped scarves and hats that recalled their death-camp uniforms.

“Auschwitz didn’t fall suddenly from the sky,” warned Marian Turski, 93, a Polish-Jewish survivor. “Auschwitz crept and tiptoed, taking small steps, it came closer, until this happened here.”

Turski begged people not to be complacent, saying the horrors of the Holocaust could happen anywhere “because if you are indifferent, you will not even notice it when upon your own heads, and upon the heads of your descendants, another Auschwitz descends from the sky.”

Set up in 1940 by Nazi Germany, the camp became the largest of the extermination centers where Adolf Hitler’s “Final Solution” of Jewish genocide was put into practice.

The fact that anti-Semitism is on the rise today is terrifying, the survivors said.

A 2019 survey by the Anti-Defamation League found that one in four Europeans subscribe to anti-Semitic stereotypes, compared with 19 percent of North Americans. In Germany, 42 percent said they believe that “Jews still talk too much about what happened to them in the Holocaust.”

“Our duty is to fight . . . those sick evils that . . . threaten to eat away at the foundations of our democracies,” Israeli President Reuven Rivlin said at the gathering, which was attended by leaders from all over the world, including Gov. Cuomo.

The event was held in a tent in a section where most of the murdered Jews were executed in gas chambers and then cremated. The camp was liberated by Soviet troops on Jan. 27, 1945.

When World War II ended, “the world finally saw pictures of gas chambers, [and] nobody in their right mind wanted to be associated with the Nazis,” said Ronald Lauder, president of the World Jewish Congress.

“But now I see something I never thought I would see in my lifetime, the open and brazen spread of anti-Jewish hatred.

“Do not be silent! Do not be complacent!” he pleaded.

In New York, there was a 26 percent jump in anti-Semitic crimes reported in 2019 compared with 2018, according to tallies from the NYPD.

With Wires