The Turkish agency which oversees religious activity has said a mosque in Germany where men and women mingle is "incompatible" with Islam.
The Ibn Ruschd-Goethe mosque in Berlin doesn't separate men and women, allowing for female imams and representatives from all sects of the faith to pray together.
Supporters of the mosque have praised it for allowing liberal Muslims to meet, but it has not been met favourably by official state institutions in Turkey.
The presidency of Religious Affairs, or Diyanet, released a statement to say these ideas were not compatible with "the basic principles" of the faith, and how it neglected all manner of its "worship, methodology, and knowledge."
It said such ideas were in line with those promoted by cleric Fethullah Gulen, blamed by the government in Turkey for last year's failed coup.
The relationship between Turkey and Germany has been rocky for several months.
In March, President Erdogan said Nazism was still alive in the country after several rallies for foreign nationals in the lead-up to the Turkish referendum were cancelled, remarks which were strongly condemned by the German Chancellor Angela Merkel.