BERLIN (Reuters) - Jewish groups in Germany are pressing the authorities to crack down on anti-Semitic acts following the burning of Jewish symbols and Israeli flags at protests.

The American Jewish Committee Berlin, the JSUD group of Jewish university students, the Central Council of Jews in Germany, and the German-Israeli Society have called for tougher law enforcement and for new laws to make it easier to ban or disband anti-Semitic demonstrations.

Chancellor Angela Merkel and other top German officials have condemned anti-Semitic acts seen at demonstrations against U.S. President Donald Trump’s decision to recognize Jerusalem as the capital of Israel, and vowed to prosecute illegal acts.

The American Jewish Committee Berlin said a new study by an Indiana University professor showed broader efforts were also needed to fight anti-Semitic attitudes among Muslim migrants from Syria and Iraq.

German has opened its borders to more than 1 million migrants mainly fleeing Middle East wars since 2015, sparking concerns about a further bump in already increasing anti-Semitism.

“Politicians must guarantee that anti-Semitic attitudes will not be tolerated and that infractions to laws and regulations will be prosecuted,” said the group’s director, Deidre Berger.

She reiterated a longstanding call for the German government to appoint an anti-Semitism commissioner to focus attention on the issue.

German Justice Minister Heiko Maas and Berlin Mayor Michael Mueller vowed during a menorah lighting at the Brandenburg Gate on Tuesday to combat all forms of anti-Semitism, while demonstrators continued to voice anger at the U.S. move at a separate event near Berlin’s main train station.

The Central Council of Muslims in Germany has also condemned anti-Semitic actions.

Indiana University’s Guenther Jikeli, the author of the study, said group interviews of 68 migrants aged 18 to 52 conducted last year revealed widespread anti-Semitic attitudes. They showed rejection of the state of Israel and ignorance about the murder of 6 million Jews in Europe by the Nazis during World War Two, he said.

“There are strong anti-Semitic views among refugees that need to be addressed because otherwise they could become the norm,” he told Reuters TV.

Kurds and other refugees persecuted as minorities in their home countries had more nuanced views and more clearly rejected anti-Semitism and anti-Israeli perspectives, he said.

Fabian Weissbarth, spokesman for AJC, said the study should spur efforts to tackle anti-Semitism among migrants to ensure the findings were not misused by anti-immigrant far-right groups like the Alternative for Germany (AfD) party.

“If we don’t address it as a society, then the AfD will, and that will lead to hate and incitement,” he said. “We need a differentiated view that recognizes that not all refugees are the same, and we need to look at solutions, such as integration measures, what needs to be included in integration courses, and changes in how social workers and politicians react.”