BERLIN (JTA) — A resident of Potsdam who was wearing a kippah with a Star of David on it was the victim of an anti-Semitic attack.

The victim reported being followed, spat upon and insulted in the weekend attack.

Police quickly arrested two men, a 19-year-old Syrian citizen and a 17-year-old of unnamed origin. The younger of the two is now being treated as a witness, not as a suspect, police told the German press agency dpa.

In a statement after news of the attack broke, Potsdam Mayor Mike Schubert said he expected swift results from the police investigation, to clarify the motivation for and legal consequences of the attack.

There must be “no tolerance for politically and religiously motivated hate and violence in our city,” he added.

According to news reports, the 25-year-old student who was attacked “always wears a kippah,” in keeping with his family’s tradition. The incident occurred as he stepped out of a streetcar at the main train station in Potsdam, outside of Berlin, on Saturday.

He noticed that he was being followed. Moments later one of the pair spat on him and shouted an anti-Semitic insult, as well as threatened him with physical violence.

The student notified the federal police, who quickly found the two young men.

Anti-Semitic crimes in Berlin, mostly hate speech, graffiti and the display of banned Nazi symbols, rose by nearly 20 percent in 2018 over the previous year, according to statistics released in May by Germany’s Interior Ministry and Federal Crime Office. At the same time, the total number of politically motivated crimes was down 9 percent.

Although Interior Minister Horst Seehofer said the vast majority of crimes — around 90 percent of the 1,800 recorded incidents, up from 951 — were attributed to far-right wing perpetrators, some observers see a connection between these trends and the influx of some 1 million Muslim refugees from war-torn countries since 2015.