At least 48 people were detained over their alleged use of ByLock mobile application during dawn raids in Istanbul on Thursday.
Detention warrants were issued for 60 people as part of an investigation into the Gulen movement which the government blames for the July 15, 2016 failed putsch.
The movement denies involvement.
Istanbul police carried out simultaneous raids at 60 locations early Thursday and rounded up 48 of the suspects.
The suspects are accused of having used ByLock mobile application, which Turkish authorities believe is a communication tool among Gülenists.
Tens of thousands of people, including civil servants, police officers, soldiers, businessmen and homemakers, have either been dismissed or arrested for using ByLock since the failed coup last year.