BERLIN

A mosque in Germany's western city of Frankfurt has been targeted overnight by supporters of the PYD/PKK terror organization who painted on the main gate threats against the Turkish Muslim community.

It was the fourth incident within a week against the mosques of the Turkish Muslim community, amid violent protests by the sympathizers of the PYD/PKK against Turkey's military operation against terrorist targets in Syria's Afrin district.

The assailants wrote the name of the PKK, and slogans such as "Revenge" and "Afrin" on the main gate of the Eyup Sultan Mosque, run by Turkish-German Muslim association DITIB.

Over the weekend, mosques in Leipzig, Kassel and Minden were also attacked by supporters of the PYD/PKK, the Syrian affiliate of the PKK, which is listed as a terrorist organization by Turkey, the U.S. and EU.

Germany's Interior Ministry spokesman condemned the attacks. "Of course this is unacceptable, such acts are criminal offenses," Johannes Dimroth told a news conference in Berlin on Wednesday.

He underlined that German authorities would investigate and take legal action against the incidents.

Turkey on Saturday launched Operation Olive Branch to remove PYD/PKK and Daesh terrorists from Afrin.

Since Sunday, supporters of the PYD/PKK have organized various demonstrations in Germany to protest the ongoing military operation.

Several Turkish citizens were punched at Hannover Airport on Monday, where the PYD/PKK supporters held an unauthorized demonstration.

The PKK has been banned in Germany since 1993, but it is still active with nearly 14,000 followers among the country's Kurdish immigrant population.

Turkey has long criticized NATO partner Germany for not taking serious measures against the PKK, which use the country as a platform for their fund-raising, recruitment, and propaganda activities.

Germany has a 3-million-strong Turkish community, many of whom are second- and third-generation German-born citizens of Turkish descent whose grandparents moved to the country during the 1960s.