Turks living in European countries, especially those who are opposed to the President Recep Tayyip Erdogan, have said they have had their passports rescinded and were only told when they visited their embassy or consulate.
Kurds, Alevis – a branch of Shia Islam – and supporters of the preacher Fethullah Gulen, said by Erdogan to be the mastermind behind the attempted coup last July, have been targeted by the Turkish authorities who have prevented them from returning to their home country.
According to one report a 33-year-old man was called to the embassy in Germany to release his Turkish citizenship so he could officially take up the German citizenship instead.
Turkey's President Recep Tayyip Erdogan
When arrived at the embassy in Hamburg, however, he was told: "We must keep the passport, as your application is being processed."
The passport was not returned and he was not given any clues as to when he was going to receive his German papers, effectively leaving him in limbo.
A spokesman for the city of Hamburg said that at least four cases are known of passports being taken away by the Turkish consulate.
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A police officer talks with the soldiers involved in the coup attempt after they surrendered
The spokesman said: "We are seeing a new phenomenon here. We are monitoring further developments and are also in contact with other authorities."
In the Turkish consulates in the cities of Hanover and Essen there has even been talk of violent clashes inside consulate grounds.
Melek Yildiz of the Alevi Community of Germany said: "We know the methods of the Turkish consulates well, because we have experienced them so many times."
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Fethullah Gulen (pictured) is accused by Erdogan of being behind the attempted coup last July
Supporters of Erdogan have increasingly leaked information about fellow Turks to their consulate if they deem them not to be supportive enough of the Turkish president.
It has been reported that at the start of the year several consulates even invited Turkish parents and teachers to report Erdogan-critical voices in schools to the consulate.
Kamal Sido, the Middle East advisor for the Society of Threatened Peoples, said he knows of several cases where people are now afraid to visit the Turkish Embassy.
He said: "They do not want the Turkish government to know where they are."
President Erdogan speaking in Ankara
The news comes after Bulgarian police on Friday removed nationalists who were blocking border checkpoints with Turkey in an effort to stop buses bringing Bulgarian ethnic Turks to vote in Sunday's election, amid growing tension between the two neighbours.
Sofia has accused Ankara of interference in its election on behalf of the DOST party that represents Bulgarian Turks, the country's largest ethnic minority. Polls suggest DOST will fall short of the four-percent vote needed to enter parliament.
Tensions between Ankara and the EU have been running high since Germany and the Netherlands blocked Turkish ministers campaigning among expatriate Turks in their countries for a referendum that would give Mr Erdogan broader executive powers.