BERLIN (Reuters) - More emphasis should be placed on the Holocaust in integration courses for migrants, Germany’s justice minister said, reflecting heightened unease among leading politicians about a spate of anti-Semitic acts including Israeli flag burnings.

More than a million migrants have arrived in Germany in the last three years, many of them fleeing conflict in the Middle East, causing concern that anti-Semitism could increase.

German police have reported protesters setting Israeli flags ablaze and using anti-Semitic slogans in Berlin and other cities in demonstrations against U.S. President Donald Trump’s decision to recognize Jerusalem as Israel’s capital.

In a piece for weekly magazine Der Spiegel, Justice Minister Heiko Maas wrote that the Holocaust, in which the Nazis killed six million Jews, and its significance needed to become an even more important part of integration courses and migrants should be tested on it in the examination at the end of their course.

“The lessons from the Holocaust need to be one of the guiding ideas in those lessons and not just some chapter of German history,” he said.

“Racism has no place in Germany, so everyone who wants to stay in Germany for the long term needs to be clear that we fight the Neonazis’ anti-Semitism and we won’t tolerate any imported anti-Semitism from immigrants either,” Maas added.

Jens Spahn, a senior member of Chancellor Angela Merkel’s Christian Democrats (CDU), told Der Spiegel he thought immigration from Muslim countries was one of the causes of recent anti-Semitic demonstrations in Berlin.

Spahn said incidents in recent days “were related to immigration from a culture in which people are not prissy about how they deal with Jews and homosexuals”.

Speaking at an event marking the 70th anniversary of the establishment of Israel, German President Frank-Walter Steinmeier said on Friday Germany needed to remember its historical responsibility, including the lessons of two world wars, the Holocaust, ensuring Israel’s security and rejecting any form of racism and anti-Semitism.

“There’s no end to this responsibility for people born afterwards and no exceptions for immigrants,” he said, adding that those who burned Israeli flags did not understand or respect what it meant to be German.

In an interview with the Funke newspaper consortium, Israel’s ambassador in Berlin Jeremy Issacharoff called for a ban on burning flags. “Anyone who burns flags questions Israel’s right to exist,” he said.

Stephan Kramer, the head of a state intelligence agency in the eastern region of Thuringia, warned in Der Spiegel that anti-Semitism was becoming “ever more uninhibited” and many Jews were too scared to identify themselves as such.