Germany's main Jewish leader says he would advise people visiting big cities against wearing Jewish skullcaps, following a street assault last week on two young men wearing them.

The attack in Berlin, in which a 19-year-old Syrian asylum-seeker is a suspect, added to growing concern in Germany about anti-Semitism.

Josef Schuster, the head of Germany's Central Council of Jews, told broadcaster Radioeins Tuesday that wearing a skullcap is right in principle, but that he was advising individuals "against showing themselves openly with a kippa in a big-city setting in Germany, and wear a baseball cap or something else to cover their head instead."

Schuster suggested three years ago that Jews shouldn't wear skullcaps in areas with large Muslim populations. But he stressed there's increasing anti-Semitic sentiment among non-migrants.

On the eve of a solidarity rally in Berlin, Schuster said that if Germans refused to stand up to anti-Semitism, "our democracy would be at risk".

"This is not only about anti-Semitism — it goes along with racism, it goes along with xenophobia. You need a clear stop sign here."

However, president of the European Jewish Association, Rabbi Margolin, called on Schuster to withdraw his comments, saying "Jews — or any other religious or ethnic groups — should not be encouraged to give up their religious attributes".

Last week, a 19-year-old Syrian refugee attacked two young men wearing Jewish kippa skullcaps in Berlin, shouting "yahudi" — Jew in Arabic — and lashing out at his victim with a belt.

A video of the assault, filmed by one of the Israeli victims, went viral on social media and sparked widespread revulsion.