Vandals wrote insulting and threatening words on the walls of Muhsin Yazıcıoğlu Culture Center and Yunus Emre Mosque.
According to the Kassel police force, the examination of the site is ongoing, and an investigation has been launched, the Daily Sabah reported.
"We condemn this despicable attack on our mosque and culture center. We demand German authorities find the responsible parties as soon as possible. Such damned actions will never harm our unity as a nation in diaspora," said the Alperen Hearths, the youth organization of Turkey's Great Union Party (BBP), which owns both places, in its statement regarding the case.
Attacks on mosques are becoming more and more frequent in Germany.
In 2019, 184 attacks on mosques were recorded in Germany – occurring on average every other day.
Most recently, on Saturday night, two unidentified people placed a pig's head on the door of the Turkish-Islamic Union for Religious Affairs' (DITIB) Fatih Mosque in the southern Germany city of Vaihingen.