Prosecutors on Monday issued detention warrants for 21 people in 11 provinces for their suspected links to the Gülenist Terror Group (FETÖ), the group that carried out the failed 2016 coup attempt.

The suspects in the operation, which was based in northwestern Balıkesir province, included 11 active-duty military officers and 10 personnel previously dismissed from the Turkish Armed Forces (TSK).

The counterterrorism units of the provincial security directorates are searching for suspects in Balıkesir, Istanbul, the capital Ankara, northern Giresun, western Manisa, central Konya, northwestern Kırklareli, southern Kahramanmaraş and eastern Erzurum, Van and Bingöl provinces.

FETÖ and its U.S.-based leader Fetullah Gülen orchestrated the unsuccessful coup of July 15, 2016, which left 251 people dead and nearly 2,200 injured.

The group was behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.