A German court decision preventing President Recep Tayyip Erdoğan from addressing a rally in Cologne via video conference runs counter to democratic values and free speech, Turkey's Minister for EU Affairs Ömer Çelik tweeted on Sunday.

"German Constitutional Court's decision on the anti-coup rally in Cologne is an utter backsliding in freedom of speech and democracy," Minister Çelik wrote in English on his official Twitter account.

The rally has been called in support of Turkey's democracy following a failed military coup on July 15-16. German media reports said authorities had intervened to prevent President Erdoğan from addressing the rally via video call due to concerns over public order.

Germany is home to Europe's largest ethnic Turkish diaspora.Turkey's Presidential spokesperson Ibrahim Kalın also said that Germany's decision to block the video conference was unacceptable and said he hoped the German authorities will have a satisfactory explanation for the decision.