Istanbul police arrested three suspects in an operation against the PYD/YPG terrorist organization on Thursday.
Police sources told Anadolu Agency that counterterrorist units launched an operation to apprehend the suspects.
Police are still looking for five suspects.
Ankara has repeatedly warned against cooperating with such groups as the PYD/PKK, YPG/PKK, and SDF/PKK, which Ankara considers as the PKK, only under different names.
The PKK — listed as a terrorist organization by Turkey, the U.S. and the EU — waged a terror campaign against Turkey for more than 30 years and has been responsible for the death of nearly 40,000 people, including those of women and children.
More than 1,200 people, including security force personnel and civilians, have lost their lives since the PKK resumed its decades-old acts of terror in July 2015.