According to Istanbul’s Chief Public Prosecutor's Office, orders to arrest 123 suspects had been issued. Authorities continue to look for other suspects, who allegedly used the ByLock messaging app during the defeated coup. They have been charged with "being members of a terror organization".

ByLock was allegedly used by members of Fetullah Terror Organization (FETO), which the government blames for being behind the coup bid.

The app is believed to have been cracked by Turkish security agencies before the coup, prompting the plotters to switch to the WhatsApp messaging service but not before tens of thousands of FETO suspects had been identified.

So far, 175 police officers have been remanded in custody on the same charge.

Led by the U.S.-based Fetullah Gulen, FETO is accused of orchestrating the coup plot 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.

The July 15 coup attempt left 241 people killed and some 2,200 injured in Turkey.