Police have so far detained 40 people after the Chief Public Prosecutor's Office in central Konya province issued arrest warrants for at least 100 suspects, including alleged senior members of the group, the source, who asked not to be named due to restrictions on talking to the media, said.
The search for the remaining suspects continues, the source added. The suspects have been accused of being members of an armed terrorist organization, managing an armed terrorist organization and terror financing.
FETO, led by U.S.-based Fetullah Gulen, has been accused of orchestrating the defeated coup of July 2016 that left at least 248 people martyred, and around 2,200 others wounded.
Turkey's government accuses the FETO terror network of staging the coup attempt as well as being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police, and judiciary.
Since the foiled coup, operations have been ongoing in the military, police and judiciary, as well as in state institutions across the country, to arrest suspects with alleged links to FETO.