Osman Kavala, 64, is a Turkish businessman, publisher and activist detained for over four years despite never having been convicted of a crime.
He was acquitted last year in nationwide protests in 2013, but was later arrested again as part of the 2016 attempted military coup.
A joint statement calling for the release of Mr. Kavala was released jointly this week by the United States, France, Germany, Canada, Finland, Denmark, the Netherlands, New Zealand, Norway and Sweden.
“Persistent delays in his trial, including merging different cases and creating new ones after a previous acquittal, cast a shadow over respect for democracy, the rule of law and transparency in the Turkish judicial system.” , indicates the press release.
The embassies of his signatories called for a “fair and speedy resolution of his case … in accordance with international obligations and Turkey’s domestic laws.”
“Noting the decision of the European Court of Human Rights on the matter, we call on Turkey to obtain his urgent release,” he added.
The ECHR called for the immediate release of Mr Kavala two years ago, ruling that there was no reasonable suspicion that he had committed an offense and accusing Turkey of detaining him in order to silence him .
The Council of Europe, the 47-member human rights body that drafted and now enforces the European Convention on Human Rights, has said it will initiate infringement proceedings against Turkey if Mr. Kavala was not released.
In response to the joint statement, President Erdogan told the crowd on Saturday that foreign ambassadors “cannot dare to come to the Turkish Foreign Ministry and give orders.”
He said: “I gave the necessary order to our Minister of Foreign Affairs and I said what should be done. These 10 ambassadors must be declared persona non grata at a time. You will take care of this immediately.
“They will know and understand Turkey,” Erdogan added of the ambassadors, telling the jubilant crowd in the city of Eskisehir: “The day they do not know and understand Turkey, they will leave.”
A host state may declare foreign ambassadors persona non grata (Latin for “unwelcome person”) “at any time and without having to justify its decision” under the Vienna Convention on Diplomatic Relations.
Doing so is usually a mechanism to expel the ambassador by depriving him of diplomatic immunity, but no official notification of the statement has yet been received by the embassies concerned.
Seven of the ambassadors represent other NATO members and their expulsion threatens to create the biggest rift between Turkey and the West in Erdogan’s 19 years in power.
Six of them belong to EU members, and European Parliament President David Sassoli tweeted: “The expulsion of ten ambassadors is a sign of the Turkish government’s authoritarian drift. We will not be intimidated. Freedom for Osman Kavala. “
A source quoted by Reuters from the German Foreign Ministry said the 10 countries were consulting each other.