The Court of Justice of the European Union will meet in Luxembourg on Thursday to rule on a long-running case involving the EU's classification of the Kurdistan Workers' Party (PKK) as a terrorist organization in 2014-20.

The case dates back to 2014, when the PKK filed a lawsuit against the decision of EU states to include it in the "terror list." The PKK was put on the list in 2002 at the request of NATO member Turkey. In 2018, the EU's highest court, the Court of Justice in Luxembourg, ruled in favor of plaintiffs Murat Karayılan and Duran Kalkan that the PKK was wrongly included on the EU terror list between 2014 and 2017. In addition to procedural errors, the ruling also refers to Abdullah Öcalan's call for peace in 2013, annulling EU Council regulations on "specific restrictive measures directed against certain persons and entities with a view to combating terrorism" that affect the PKK.

The court based its ruling on the fact that the Council had not sufficiently justified the decisions to classify the PKK as a terrorist organization, which were reviewed every six months. The court considered that these decisions could no longer justify continued listing in light of the peace negotiations in 2013. In addition to the peace negotiations, the issue reportedly involves developments in 2015 related to the fight against the Islamic State (IS).

Although, as of 2015, the Council had included a French judgment in which some individuals had been convicted of supporting the PKK in the justification for listing, this judgment was also considered an old fact. In its defense, the Council had also invoked facts alleged to be terrorist in nature and committed by the PKK. However, the PKK has comprehensively denied these facts.

The Council of the EU appealed against the ruling, whereupon the Court of Justice overturned it. The PKK was again classified as a terrorist organization by the Council in January 2019, and PKK representatives filed a new application against it. This second case concerns the 2019-2020 lists.

On Thursday, the court will convene to rule on the council's decisions and lists for 2014 to 2020.