BERLIN — Across Europe, the conflict in Gaza is generating a broader backlash against Jews, as threats, hate speech and even violent attacks proliferate in several countries.

Most surprising perhaps, a wave of incidents has washed over Germany, where atonement for the Holocaust and other Nazi crimes is a bedrock of the modern society. A commitment to the right of Israel to exist is ironclad. Plaques and memorials across the country exhort, “Never Again.” Children are taught starting in elementary school that their country’s Nazi history must never be repeated. Even so, academics say the recent episodes may reflect a rising climate of anti-Semitism that they had observed before the strife over Gaza.

This week, the police in the western city of Wuppertal detained two young men on suspicion of throwing firebombs at the city’s new synagogue; the attack early Tuesday caused no injuries. In Frankfurt on Thursday, the police said, a beer bottle was thrown through a window at the home of a prominent critic of anti-Semitism. She heard an anti-Jewish slur after going to the balcony to confront her assailant, The Frankfurter Rundschau reported. An anonymous caller to a rabbi threatened last week to kill 30 Frankfurt Jews if the caller’s family in Gaza was harmed, the police said.

The string of incidents comes after Chancellor Angela Merkel condemned anti-Semitic chants from pro-Palestinian demonstrators and President Joachim Gauck called on Germans to “raise their voices if there is a new anti-Semitism being strutted on the street.”