German-Turkish diplomatic spat heightens following pro-Erdogan rally ban

A diplomatic storm is brewing between Ankara and Berlin after authorities withdrew permission for an event in the southwestern German town of Gaggenau, where supporters of Turkish President Recep Tayyip Erdogan were expected to meet on Thursday.

Turkish Justice Minister Bekir Bozdag had planned to meet with Turkish voters living in Germany to rally support for constitutional measures aimed at expanding Erdogan's powers ahead of a referendum set to take place on 16 April.

However, Bozdag announced on Thursday that he would be cancelling the visit during which he was also expected to meet with his German counterpart Heiko Mass.

"It is unacceptable that the German authorities are not tolerating a meeting of the Turkish community, while they are always lecturing everyone on human rights, democracy, rule of law and freedom of expression," Bozdag told reporters in Strasbourg, France.

"I have called off our meeting with Germany's justice minister, after the cancellation of the gathering in Gaggenau. This meeting will not take place, we will return to Turkey," he said.

Authorities in Gaggenau, according to Deutsche Well, cancelled the event stating that the hall where the event was set to take place was too small. 

German media further quoted the town's mayor Michael Pfeiffer saying that the decision was not politically motivated. 

The event had been organised by the Union of European Turkish Democrats (UETD) - seen as a pro-Erdogan lobby group. 

However, authorities in Berlin have also faced pressure from Germany's Left Party, and the right-wing, anti-immigration Alternative for Germany party to take a stronger position against Turkish officials campaigning in the country.

Around 1.4 million of the three million people of Turkish descent are eligible to vote in Turkey's 16 April referendum.

In a further development on Thursday, the Turkish government summoned Germany's ambassador to Ankara to protest the Gaggenau cancellation according to diplomatic sources who spoke to Agence France Press.

"Our discomfort and our reaction to these developments have been communicated in person to the German ambassador who was summoned this evening to the (foreign) ministry," said the senior Turkish official who spoke on condition of anonymity. 

A number of Turkish politicians have added their voices to criticism of the measure taken by German authorities. 

Turkey's Minister of EU Affairs Omer Celik was quoted in Turkish-stated owned news agency Anadolu News likening the move to an "ideological Berlin wall which separates people" claiming that German authorities were "preventing [the exercise of] a democratic right".

Relations between Ankara and Berlin have been strained since a failed military coup on 15 July 2016. 

Authorities in Berlin are demanding the release of Deniz Yucel, a German journalist with Die Welt detained in Istanbul over reports written in the aftermath of the attempted coup. 

Meanwhile Ankara has demanded that Berlin extradite alleged supporters of Fethullah Gulen - who Turkish officials say was the mastermind of the July 15 coup attempt. A request that has been been  turned down by German officials. 

(Agencies contributed to this report)