(JTA) — Israeli flags were burned in front of two synagogues in Germany and the words “Free Palestine” were spray-painted on another one in Spain.

The incidents this week are among the first manifestations of antisemitism in Europe connected to the escalation of the Israeli-Palestinian conflict in which six Israelis and at least 50 Palestinians have died in the exchange of rocket fire.

In Germany, police arrested 13 people in Muenster after witnesses reported “a group of about 15 with Arabic appearance” shouting and burning an Israeli flag in front of the synagogue.

In Bonn, police arrested three suspects in their 20s in connection with the burning of an Israeli flag outside a synagogue. A window in the door of the synagogue had been shattered.

Bishop Batzing, chairman of the German Bishops’ Conference, called the incident an “unjustifiable act of pure antisemitism.”

The incident in Spain happened in Ceuta, an enclave of that kingdom in North Africa. In addition to the slogan about Palestine, the perpetrators write AUAH, which stands for “Allah hu akbar,” “Allah is the greatest” in Arabic.

In London, thousands protested against Israel on Tuesday in a rally that turned violent when some demonstrators tried to lunge at a smaller gathering of pro-Israel protesters who had gathered there with the Israeli flag. Police separated the groups and extracted the pro-Israel demonstrators amid chants of “shame on you” and “f***ing Jews” by some of the pro-Palestinian demonstrators.