At least 25 people were detained on early Tuesday as part of an investigation into Gulen movement, which the government accuses of masterminding the July 15, 2016 coup attempt.
Some 400 police carried out raids to detain 25 suspects in Istanbul, Sanliurfa and Adana provinces, among them those who were earlier dismissed from their jobs as public servants.
The detainees are accused of having used ByLock, a controversial mobile application that the government claim to be the top communication tool among Gulen movement followers.
The government has already detained more than 120,000 people and jailed some 50,000 over alleged or real links to the movement.
Tens of thousands of civil servants, police officers and businessmen have either been dismissed or arrested for using ByLock since a failed coup attempt last July.