The Berlin Public Prosecutor's Office suspects that a classified German government document regarding Turkish supplies to Syrian rebels was passed on by a member of the leftist party Die Linke to the Workers Party of Kurdistan (PKK), a rebel group based in Turkey, German newspaper Welt am Sonntag reported.
The copy of the document revealing German intelligence data on Turkish military support for the Islamist rebel group in Syria initially appeared in August in a PKK-affiliated newspaper as well as left-wing Turkish news outlets. German parliament member Katrin Kunert, who made the inquiry, is suspected of leaking the data although she denies the charges.
The document has Kunert's inquiry and the reply: "From mid-November 2014 reconnaissance data shows that Ankara is supplying an armed rebel force in Syria. The recipient is most likely Ahrar al-Sham (the Islamic Front)."
Kunert denied the accusations, saying that she did not see the reply to her inquiry herself. The president of the Bundestag, Germany's lower-house of the legislature, has filed charges with the Berlin prosecutor's office which will carry out the investigation.
Turkey's conflict with the PKK has escalated in recent months, with numerous casualties among military, police and civilians resulting from clashes with PKK fighters. Since July, Turkey has attacked PKK positions in northern Iraq, where Kurdish groups are battling ISIL.