Turkey has summoned a senior German diplomat, the embassy said, a day after German authorities stopped Turkey's president from addressing a rally in Cologne via video-link.
"The charge d'affaires has been summoned to the Turkish foreign ministry at 1pm (10:00 GMT)," a spokeswoman for the German embassy in Ankara told the AFP news agency, adding that the ambassador, who was summoned originally, was not in town.
Tens of thousands of supporters of President Recep Tayyip Erdogan rallied in Cologne on Sunday to show their opposition to a failed coup on July 15, which had aimed to topple him.
Hours before the demonstration, Germany's constitutional court banned an application to show live speeches from Turkey by politicians including Erdogan, amid fears that political tensions in Turkey could spill over into Germany.
READ MORE: Turkey detains 11 involved in bid to 'kidnap' Erdogan
The decision sparked anger in Turkey, with presidential spokesman Ibrahim Kalin calling the ban unacceptable and a "violation of the freedom of expression and the right to free assembly".
Germany is home to three million ethnic Turks, making up Turkey's largest diaspora, and tensions over the failed coup have put authorities there on edge.
The tension comes at a time when relations between Germany and Turkey are already strained over the German parliament's decision to brand as genocide the World War I-era Armenian massacre by Ottoman forces.
Top US general visits
Separately, Turkey's military and political leaders were due to meet in Ankara with the top US military commander in the first direct talks since the failed coup.
General Joseph Dunford, chairman of the US joint chiefs of staff, was to meet with Turkish chief of staff General Hulusi Akar and Prime Minister Binali Yildirim.
Tensions between the two NATO allies have been aggravated by the foiled putsch. Some Turkish officials allege that Washington could have had a hand in the plot, a suggestion that has been firmly denied by top US officials.
READ MORE: Turkey - United against a coup, divided on the future
Turkey successfully thwarted the attempted coup, blaming it on a military faction loyal to Erdogan's arch-foe Fethullah Gulen, a US-based businessman who has been in self-imposed exile since 1999.
Turkey is now requesting his extradition from Pennsylvania.
"We do not want (the US) to be in a position that will make us question our friendship," Yildirim told Turkish media.
"If they keep on dragging (their) feet on the Gulen issue ... then things will take a different course because events of July 15 are crystal-clear."
Last week, Erdogan lashed out at the top US general in the Middle East, General Joseph Votel, after he expressed concerns about the future of military relations between the two allies in the wake of the attempted coup.
Tens of thousands have lost their jobs and almost 19,000 people have been detained across Turkey in a post-coup crackdown, sparking international concern.