Four people who were planning to cross into Greece illegally were arrested in Turkey's northwestern Edirne province for their suspected links to the Gülenist Terror Group (FETÖ) on Saturday, military sources said.

The suspects caught near the prohibited military zone between Greece and Turkey included an ex-colonel, Mahmut Erel, who had been wanted by Turkish security forces for "being a member of a terrorist organization."

Another suspect Sabri A. was also wanted for the same charge, while two others, M.K. and E.K. were users of ByLock, an encrypted cellphone app used by FETÖ coup plotters.

FETÖ and its U.S.-based leader Fetullah Gülen orchestrated the defeated coup of July 15, 2016, which left 251 people killed and nearly 2,200 injured. Ankara also accuses FETÖ of being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.