In the seven decades since the end of World War II, Germany has refused to gloss over its Nazi past. Holocaust education is mandatory in schools, and in the late 1980s and early ′90s the country welcomed tens of thousands of Jews from the former Soviet Union.

“For many Germans, no one in their right mind would be anti-Semitic and there is an astonishment that they have to deal with it again,” said Doron Rubin, the head of Berlin’s Kahal Adass Jisroel community organization.

Making such amends is also widely seen as playing into Merkel’s decision to open Germany's borders to migrants in 2015, when around 1 million asylum-seekers reached the country, which had a population of 81 million. At times more than 10,000 people were arriving daily. Some migrants brought a hatred of Israel and belief in conspiracy theories involving Jews with them.

There are around 100,000 Jews in Germany, and the vast majority are relatively secular and don’t outwardly display signs of their faith.

However, an Israeli Arab who wore a kippah in Berlin last month as an experiment was subjected to verbal abuse and was lashed with a belt by a teenage Syrian refugee. The incident was captured on video and quickly spread on social media.

When word of the attack spread, several cities around Germany hosted kippah marches with participants of all religions wearing the traditional head covering in solidarity.

A Jewish man in Berlin hides his kippah under a baseball cap. HC Plambeck / for NBC News

The success of far-right populists at the ballot box has also set off alarm bells. The anti-immigration Alternative for Germany (AfD) party won more than 5.8 million votes in parliamentary elections in September — or around 13 percent of the ballots cast.

Felix Klein, the federal government's new commissioner tackling anti-Semitism, has accused the AfD of helping make such views “presentable” again by challenging a longtime consensus about how to deal with the country's fascist past.

Referring to Berlin's Holocaust memorial, one senior AfD politician last year said that "Germans are the only people in the world who plant a monument of shame in the heart of the capital.”

However, Klein said that "discussion about drawing a line" under the Holocaust "is very dangerous."

While the Jewish community is closely monitoring the rise of the AfD, the views and actions of the more than 1 million migrants who arrived since 2015 is a more immediate concern for some.

“Jews live side by side with migrants more than with the right-wingers who are often in rural areas or outside big cities,” said Sergey Lagodinsky, who is Jewish and a community board member in Berlin.

The number of anti-Semitic crimes in Germany increased by 2.5 percent during 2017, according to official figures. Overall crime was down by 9.6 percent last year.

Interior Minister Horst Seehofer said that while "imported anti-Semitic crimes" were rising, he pointed out that "almost 95 percent of anti-Semitic crimes in 2017 had a right-wing motive."

Either way, anti-Semitic incidents — which include those not considered criminal offenses — do appear to have been rising as a whole.

In 2017, 947 anti-Semitic incidents, including 18 attacks, were reported in Berlin to Research and Information on Anti-Semitism, an organization founded to record and publicize such events — no matter how small. The group said that represented a 60 percent year-on-year increase in reports.

They include several cases of Jewish children attending schools with large Muslim populations who transferred after classmates had taunted or mobbed them.

Liam Rueckert, 15, says he was subjected to such severe abuse at school last year — he said classmates would call him "s--- Jew" or "s--- Israeli" in German — that he refused to attend. He is now enrolled in a practical skills training course instead.

“It happened at least once a week,” Rueckert said. "Nothing happened to them. I would never go back.”

Muslim community leaders say concerns about anti-Semitism among migrants and their children is exaggerated and lets the far-right off the hook for its intolerance.

Dervis Hizarci is the head of the Kreuzberg Initiative Against Anti-Semitism. HC Plambeck / for NBC News

“Even if every Muslim was anti-Semitic, which would obviously be bad, they aren’t the ones who rule here,” said Dervis Hizarci, the head of the Kreuzberg Initiative Against Anti-Semitism, which works with young people brought up in Muslim communities in Berlin.

There are nearly 5 million Muslims in Germany, around 6.1 percent of the population, according to the Pew Research Center.

Hizarci is no stranger to intolerance himself. A former high school teacher, he was once turned away when trying to rent an apartment because of his Turkish roots.

According to Hizarci, refugees tend to easily learn tolerance because of their backgrounds in facing persecution themselves.

"Germany has difficulty accepting that it is an immigrant country," he added. "With the migration crisis it got even more complicated."

Graffiti artist and shop owner Ibo Omari is trying to spread a similar message in his neighborhood.

Two years ago, a customer told him that a Nazi flag had been painted at a local playground.

Instead of erasing the swastika, Omari used spray paint to turn the image into a mosquito flying into a net.

He repeated the trick whenever a new swastika popped up.

Swastikas are turned into mosquitoes on walls in Berlin, Germany.

“The problem is that many people don’t feel at home so they don’t feel responsible,” said Omari, 37, whose mother was born in Turkey and his father in Lebanon.

Through a nonprofit organization called The Cultural Heirs, he now runs graffiti workshops for children — including many from migrant families — to give them a feeling of belonging to their community.

Whether such local efforts are enough to change what the Jewish community believes is a growing problem remains up for discussion.

Jewish community leaders are pressing the government to implement further tolerance and anti-Semitism education in schools, as well as to send a strong signal that migrants with anti-Semitic views aren’t welcome.

Ibo Omari. HC Plambeck / for NBC News

Klein, the commissioner appointed by Merkel's government to coordinate activities against anti-Semitism, started in the post on May 1.

“Of course we have a new challenge and new forms of anti-Semitism which we have to address and combat, but the great problem also rests with right-wing anti-Semitism and we have to develop good strategies to combat that, as we did before," he said at a news conference in late April.

But Rabbi Yehudah Teichtal, of the Jewish Community of Berlin, insisted that tackling the issue needs to be made more of a priority.

Berlin Community Rabbi Yehuda Teichtal. Markus Schreiber / AP file

“I’ve never seen the worry that I have in the last three months,” Teichtal said.

Someone in a passing car shouted an anti-Semitic slur at Teichtal as he walked home from synagogue on a Friday evening with his 5-year-old son several weeks ago.

“I’m telling the government they need to do more," he said. "I’m an optimist though. We are here to stay and full of trust, but more has to be done.”