On Friday, the court accepted an objection filed by the Istanbul prosecutor’s office to the activists’ release, Turkey’s official news agency Anadolu reported.
The activists were initially released on Tuesday after submitting their passports and they were required to regularly report to a police station.
The activists are part of a group arrested earlier in July on an Istanbul island during a digital security training course.
Earlier this week, a court in Istanbul decided to continue the detention of Amnesty International’s Turkey director Idil Eser along with five other activists, including a German national identified as Peter Steudtner, over allegations of links to Kurdish militia and the alleged plotter of last year’s attempted coup.
The court, however, decided to release four other activists pending the outcome of a trial.
The ten activists were arrested on July 5 during a police raid on a hotel on the island of Buyukada south of Istanbul, where they attended a workshop on digital security and information management.
Two of the arrested activists were foreign trainers of the digital information workshop, a German and a Swedish national. The remaining eight were Turkish human rights defenders, including Ilknur Ustun of the Women’s Coalition and Veli Acu of the Human Rights Agenda Association.
Berlin slammed the detention of the six activists, including German national Steudtner, as “unjustified.”