Turkey must produce clear evidence in pursuing participants in a failed coup and avoid targeting teachers and journalists simply because they worked for firms run by the Muslim cleric Ankara portrays as its mastermind, the head of the European rights watchdog said.
Otherwise, said Thorbjorn Jagland, Turkey may be challenged in the European Court of Human Rights in Strasbourg, which is tasked with enforcing the European Convention on Human Rights.
Turkey said the judicial process would be fully transparent.
President Recep Tayyip Erdogan has cracked down on schools, media and businesses run by U.S.-based cleric Fethullah Gulen since the July coup. Several thousand soldiers have been expelled from the army, and more than 100,000 people, including civil servants, teachers, journalists and soldiers, have been suspended or sacked.
"We are stressing to the Turks that they have to present clear evidence, be able to separate those who were clearly behind the coup and those who have been in some way or another connected to or working for this so-called Gulen network," Jagland, secretary general of the Council of Europe, told Reuters.
"They are not necessarily guilty. For teachers and journalists that worked in schools or media outlets of Gulen, you cannot say automatically that because they've done that, they are part of this military coup."
Gulen has denied being behind the coup.
Turkey has accused the European Union of applying a double standard in criticizing the crackdown while, in its view, showing hesitation in condemning the coup that killed about 240 people.
Western officials have said they fear Erdogan may use the action as a cover for suppressing any opposition.
Jagland was speaking after Turkish Foreign Minister Mevlut Cavusoglu briefed representatives of Council of Europe states in Strasbourg, France, on the situation in his country after the coup.
Speaking to reporters before the council session, Cavusolgu outlined plans for dealing with the aftermath of the coup.
"Be assured that this process will be very transparent and the supervision of the European Court of Human Rights is still valid and the Convention on Human Rights is also a guideline for Turkey even during this difficult time," he said.
Jagland is also trying to persuade Turkey to apply its counterterrorism laws more narrowly. The European Court of Human Rights in Strasbourg has in the past ruled against convictions of journalists on the basis of these regulations.
While Turkey is a member of the council, it is not in the European Union. The 28-nation bloc made easing visa requirements for Turks traveling to the EU conditional on changing the terrorism laws. Turkey says it needs a broad interpretation of such regulations to meet a threat from Kurdish rebels and from Islamic State militants.
"Journalists who have reported on the work of terrorist organizations, which is the job of journalists — you can't say one supports terrorists by reporting on them," Jagland said.