A European human rights watchdog will refer the Turkish case against philanthropist Osman Kavala back to a top European court, Turkey's foreign ministry said on Wednesday, adding that the move amounted to interfering in its judiciary.

Kavala, one of Turkey's highest-profile detainees, has been held for more than four years without a conviction.

The European Court of Human Rights (ECHR) ruled more than two years ago that Kavala should be released immediately and said his detention served to silence him, but Turkey has not carried out the ruling.

A spokesman for the Council of Europe, of which Turkey is a founding member, did not confirm the decision by its Committee of Ministers, which met on Wednesday. He said its decision was due to be published on Thursday.

The question of whether Turkey has violated the European Convention on Human Rights by not executing the court's judgment will now be referred back to the ECHR. The move is the next step in an "infringement proceedings" process that could lead to Ankara's suspension from the Council of Europe.

Nacho Sanchez Amor, Turkey rapporteur for the European Parliament, said: "This is what happens when a legally binding ruling is blatantly ignored."

Turkey's Foreign Ministry said the country had told the Committee that the detention was due to another judicial process and the ECHR ruling had been carried out.

"It is evident that this prejudiced decision, taken with political motives by disregarding an ongoing internal judicial process, damages the reputation of the European human rights system," it said.

The ministry said the Committee's decision, taken by a majority of votes, amounted to interfering in the judicial process and was "far from being done with good intentions".

Kavala was acquitted in 2020 of charges related to 2013 nationwide protests. Hours later, another court ordered his arrest based on a charge of attempting to overthrow the constitutional order related to the 2016 coup attempt, which the ECHR had also said lacked basis.

That court later ruled to release him on that charge but ordered his detention on an espionage charge in the same case, a move critics said was aimed at circumventing the ECHR ruling.

Kavala said in a statement on Wednesday: "I hope the evaluation that the ECHR delivers will contribute to the preservation of judicial norms regarding human rights in Turkey."