An Istanbul court yesterday scrapped its decision to release Taner Kilic, the head of Amnesty International in Turkey, and ordered him to remain in jail for the duration of his trial on terror charges, the rights group said.

"The Istanbul court has now overturned its own release verdict... Taner will stay in pre-trial detention," Turkey's Amnesty researcher Andrew Gardner said on Twitter.

"This is devastating for Taner's family and a disgrace to justice," he added.

Kilic has been held since June 2017 in the western city of Izmir, accused of links to US-based preacher Fethullah Gulen who Turkey says ordered the July 2016 coup bid.

Amnesty has denounced the allegations against Kilik as "baseless".

Gulen and his followers meanwhile deny any links to the coup, and reject the Turkish government's attempt to label them as a terrorist group.

The Istanbul court had on Wednesday ordered his release on judicial control, to the delight and relief of his family and friends.

But their joy was sapped hours later after he was taken back into custody straight after his release.

Authorities accused Kilic of having an encrypted messaging application on his phone in August 2014 called ByLock, which Ankara claims was especially created for Gulen supporters.