AMSTERDAM (Reuters) - Turkey has sentenced a U.N. war crimes judge to 7 years and six months in prison on charges of “membership in a terrorist organization”, an international court in the Hague said on Thursday.

Judge Aydin Sedaf Akay has been held in Turkey since September, one of tens of thousands of Turkish officials arrested in a crackdown on people and organizations after a foiled coup in which hundreds died.

The U.N. court said in a statement that Turkey’s actions constituted a “further breach of Judge Akay’s protected status”, as U.N. judges have diplomatic immunity under international law.

Akay is a judge at the MICT, the Hague court set up to handle final appeals and other remaining cases from the Yugoslav and Rwanda war crimes tribunals, which are being wound down.

At the time of his arrest, Akay was part of a panel assembled to determine if new evidence showed Rwandan Augustin Ngirabatware had been wrongfully convicted of genocide and jailed for 35 years.

That proceeding has been delayed by Akay’s absence.

According to a statement by the MICT, Akay was convicted on Tuesday on a single charge of membership in “FETO” - which Turkey says is a terrorist organization that supports U.S.-based cleric Fethullah Gülen whom Ankara accuses of backing the coup.

MICT President Theodor Meron said that Akay’s arrest, “detention, and legal proceedings against him are inconsistent with the assertion of his diplomatic immunity by the United Nations, as well as the binding judicial order (to release him that the MICT) ... issued in January 2017.”

In March Meron reported Turkey to the UN Security Council over the matter.