The northern German city of Hanover on Thursday barred a political meeting by supporters of Turkish President Recep Tayyip Erdogan's Justice and Development Party (AKP) at which a senior party official was to speak.
The move was likely to further hike tensions between Ankara and Berlin sparked by a ban on political rallies to ramp up support for a "Yes" vote in Turkey's April referendum on expanding Erdogan's powers.
The issue has also sparked a major diplomatic crisis between Turkey and the Netherlands as well as a handful of other European states.
"We want to make it very clear that we don't want such electoral meetings in our city," said Stefan Schostok, mayor of this city of 500,000 that is the capital of the German state of Lower Saxony.
"As mayor, I refuse to let an internal Turkish conflict be brought to our city," he said.
According to Hanover city hall, the Union of European Turkish Democrats (UETD) had asked for permission for a gathering which it characterised as a local gathering to discuss internal Turkish issues.
But after the city council discovered that Mehmet Mehdi Eker, one of the AKP's vice presidents, was due to speak, they banned the meeting.
Eker has already spoken at several rallies of AKP supporters in Germany ahead of the April 16 referendum.
The diplomatic crisis erupted after several German towns refused to allow political rallies at which Turkish ministers and officials were due to campaign, sparking a furious reaction from Ankara.
Germany is home to the largest Turkish diaspora, with 1.4 million people who are eligible to vote in the referendum.
- Rotterdam okays rally -
A similar move in the Netherlands went even further, with the Turkish foreign minister's plane blocked from landing ahead of a campaign rally in Rotterdam and another minister expelled, sparking a bitter diplomatic row.
In response, angry pro-Erdogan demonstrators clashed with police outside the Turkish consulate in Rotterdam, with police using dogs, horses and water cannon to disperse them.
But in a surprise move, the city's mayor on Thursday granted authorisation for a pro-Turkish demonstration outside the train station to protest over the police's handling of Saturday's unrest.
Elsewhere in Europe, an Austrian concert hall cancelled a Turkish music event over its apparently "political" nature, citing the performers' links to Turkish nationalists who are allied with with the AKP.
Austria has also cancelled a series of political events by AKP figures.
There are 250,000 Turks living in the Netherlands who are eligible to vote in next month's referendum and another 109,000 living in Austria, with support for the ruling AKP high among both groups of voters.
Despite German efforts to calm the situation, the crisis has steadily worsened, with Turkey on Wednesday threatening to cancel a key deal with Brussels which has considerably reduced the flow of migrants and refugees to the EU.