Police detained 12 Turk Telecom employees in Istanbul on Tuesday as part of a probe into the Fetullah Terrorist Organization (FETÖ).
According to Istanbul's Chief Public Prosecutor's Office, orders to arrest 22 suspects had been issued.
The authorities continued to look for the remaining suspects, sought on charges of "being members of a terrorist organization". The Istanbul-based operation is ongoing in other parts of Turkey, including Agri, Malatya and Ankara provinces.
So far 144 Turk Telekom employees have been taken into custody while several Turkish courts have remanded 63.
The Turk Telecom staff members were detained over suspected links to the FETÖ group.
They face charges of violating the constitution, treason and membership of a terrorist organization.
Meanwhile, at least 20 people were also arrested across eight provinces for allegedly using a smartphone messaging app called ByLock which has been linked to the coup plot.
The operation focused on FETÖ structures in Turkey's prison system. Among those detained was the governor of Istanbul's Silivri Penal Institution.
According to Istanbul's Chief Public Prosecutor's Office, orders to arrest 25 suspects had been issued.
The Istanbul-based operation is ongoing in Ankara, Bursa, Canakkale, Kirikkale, Tokat, Ordu and Rize provinces simultaneously.
In the wake of the coup attempt, tens of thousands FETÖ suspects have been arrested, including many in the armed forces, police, justice system and education sector.