Ten human rights activists including Amnesty International's Turkey director were sent to an Istanbul court late on Monday in a case Amnesty slammed as a "travesty of justice".
Idil Eser, director of Amnesty International Turkey, was detained on July 5 along with seven other activists and two foreign trainers during a digital security and information management workshop on Buyukada, an island south of Istanbul.
Their detention sparked international alarm and amplified fears of declining freedom of expression under President Recep Tayyip Erdogan.
"All requested for pre-trial (detention) and sent to court," Amnesty International's Turkey researcher Andrew Gardner told AFP.
That came after the activists, who are not yet on trial, gave statements to prosecutors for the first time since their detention.
Gardner said either the court could decide to release the detainees or "unfortunately, we could see the continuation of this process where the government has targeted all critical voices, in particular human rights civil society."
A decision was "hours away", he added, with the Istanbul court expected to make a decision early Tuesday.
Some of the relatives of the activists, who gathered outside the courthouse, looked worried and refused to speak to the journalists.
Eight of those detained are Turkish rights activists, including Ilknur Ustun of the Women's Coalition and Veli Acu of the Human Rights Agenda Association.
Two are foreign trainers -- a German and a Swedish national -- who were leading the digital information workshop.
They are accused of membership of an "armed terrorist organisation", an allegation Amnesty said was "unfounded".
Speaking to journalists outside the Istanbul court early Monday, Gardner said if the activists were remanded in pre-trial prison custody, "that would be a travesty of justice," and called for their immediate release.
"This is a test for Turkey's judiciary," he said.
"Turkey will be disgraced in the eyes of the world if these human rights defenders are put in prison for defending human rights."
President Recep Tayyip Erdogan said this month that the activists were detained on a tip-off that they were working against the government, comparing them to coup plotters involved in a failed putsch in July last year.
Gardner said the meeting on Buyukada had been a "routine" workshop and there was nothing suspicious about it.
"What is absolutely crystal clear, one hundred percent clear is this was a routine human rights workshop -- the sort of workshop that happens all over Turkey, in fact the sort of workshop that happens all over the world," he said.
Last month, Amnesty International's Turkey chair Taner Kilic was arrested, accused of links to US-based preacher Fethullah Gulen, who is accused of ordering last year's failed coup, a charge he denies.
Gardner said country director Eser remained "in good spirits."
"She sent messages that as soon as she is released she wants to carry on from where she left off," he said.