Director of Turkey for Amnesty International Taner Kılıç was kept in custody Thursday after an appeal of the prosecutor to the court order for his release.
On Wednesday, an Istanbul court had ordered Kılıç's conditional release and imposed a travel ban on him while his trial on terrorism charges continues.
Kılıç was the only jailed suspect among 11 defendants charged on membership in a terrorist group and aiding a terrorist organization and was linked to the Gülenist Terror Group (FETÖ) blamed for the 2016 coup attempt.
Authorities detained him in June 2017 for links to FETÖ, particularly for his use of ByLock, an encrypted messaging app exclusively used by the terrorist group. Kılıç denied having the app and claimed Bylock was downloaded to his phone without his knowledge when he downloaded religious-themed apps.
Authorities last year announced that hundreds were unwittingly connected to ByLock when they downloaded religious apps to their phones. The trial was adjourned to June, while the court ruled that defendants are not required to attend the next hearing.