The court in Silivri on the outskirts of Istanbul issued the ruling in the second hearing of his trial which began last month, Kavala's lawyer Ilkan Koyuncu told AFP.

The trial was adjourned until October 8 and 9.

Earlier on Thursday Kavala told the court "there is no concrete evidence against me" as he demanded his release. The prosecutor opposed any release for the trial's duration.

Kavala is among a group of 16 Turkish businessmen, academics and artists on trial, suspected of trying to oust President Recep Tayyip Erdogan during mass protests in 2013.

He is accused of orchestrating and funding the protests, which began over government plans to build over Gezi Park, one of a limited number of Istanbul's green spaces.

Six of the suspects are being tried in absentia after fleeing Turkey, including actor Memet Ali Alabora and dissident journalist Can Dundar.

They risk life in jail if convicted in a case dismissed by rights defenders as "absurd".

Kavala has been in detention since November 2017, and has become a symbol of what activists say is the deliberate targeting of civil society.

He was among tens of thousands of people including activists detained following the July 2016 coup bid and the two-year state of emergency imposed shortly afterwards.

A respected figure in intellectual circles, Kavala is chairman of the Anatolian Culture Foundation, which seeks to bridge ethnic and regional divides through art, including with neighbouring Armenia, with which Turkey has no diplomatic ties.

Amnesty International Turkey researcher Andrew Gardner said it was "obvious" Kavala was being punished "for his civil society activities and to intimidate other civil society actors".

"We call for Osman Kavala to be released and charges against all 16 to be dropped," Gardner said.