Turkish police detained 12 employees from the country's largest telecom service provider in Istanbul on Tuesday as part of a probe into the Gülenist Terror Group (FETÖ).
According to Istanbul's Chief Public Prosecutor's Office, orders to arrest 22 suspects from executives of Türk Telekom had been issued.
The authorities are continuing 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 Ağrı, Malatya and Ankara provinces.
So far 144 Türk Telekom employees have been taken into custody while several Turkish courts have remanded 63.
The Türk Telekom staff members were detained over suspected links to the FETÖ group, which is accused of orchestrating Turkey's defeated July 15 coup attempt which saw 248 people killed and nearly 2,200 injured.
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 warden of an open-type prison in Istanbul's Silivri Penal Institution, where many FETÖ suspects are currently being kept in closed-type sections of the complex.
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, Çanakkale, Kırıkkale, Tokat, Ordu and Rize provinces simultaneously.
Turkey's government has said FETÖ, which is led by U.S.-based Fetullah Gülen, is behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.
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.