Protesters waving Palestinian flags and signs of late leader Yasser Arafat have in recent days shouted anti-Semitic slogans at rallies against Israel's Gaza offensive, according to German media.
Exclaiming "Allahu Akbar" (God is great), crowds in Berlin have reportedly yelled "Death to Israel" and chanted "Zionists are fascists, killing children and civilians."
A Berlin imam has openly called for the annihilation of Zionist Jews, asking Allah to "kill them to the very last one."
The president of the Central Council of Jews in Germany, Dieter Graumann, said: "We are currently experiencing in this country an explosion of evil and violent hatred of Jews, which shocks and dismays all of us.
"We would never in our lives have thought it possible anymore that anti-Semitic views of the nastiest and most primitive kind can be chanted on German streets," he said in a statement.
He demanded "clear and loud condemnations from politicians, the media and civil society" against the hatred in the country that perpetrated the Holocaust.
"Jews are once again openly threatened in Germany and sometimes attacked, synagogues are being defaced and declared as targets," he said.
"This new dimension of anti-Semitism has received far too little attention. Anti-Semitism must not be concealed, it must be addressed and combated resolutely! Freedom of speech yes, but no to hate speech!"
The centre-left Social Democrats party in a statement agreed, declaring: "Anti-Semitism, in whatever form, is in no way acceptable. Whoever supports or propagates is not in their right mind."
Berlin police, meanwhile, told Berlin daily Tagesspiegel that officers would from now take action if protesters repeat certain phrases from past rallies, including "Jew, Jew, cowardly pig, come out and fight alone."
The American Jewish Committee meanwhile demanded that German prosecutors investigate the reported statements of the imam, identified by the committee as Bilal Ismail, in the sermon delivered last Thursday.
"It must bring down the weight of the law against the preacher. Incitement to murder cannot be justified," said Deidre Berger, director of the committee's Ramer Institute for German-Jewish Relations.
Pro-Palestinian demonstrations have been held in recent weeks in cities across Europe, including in France where they have spiraled into violent clashes with riot police and dozens of arrests.