Berlin, Oct 26 (IANS): Turkish authorities have released German human rights activist and documentary maker Peter Steudtner on bail within hours of the start of his controversial terrorism trial in Istanbul, officials announced here on Thursday.

Steffen Seibert, the official spokesperson for German Chancellor Angela Merkel, welcomed the development on Twitter, reports Xinhua news agency.

"Finally, Peter Steudtner and further human rights activists are free," he tweeted.

The spokesperson added that the government was happy for Steudtner, but also "thinking about those who are still imprisoned".

According to RedaktionsNetzwerk Deutschland, former German Chancellor Gerhard Schroeder is said to have negotiated the release with Turkish President Recep Tayyip Erdogan.

German Foreign Minister Sigmar Gabriel called Steudtner's release an "encouraging sign" while noting that other German citizens were "still in Turkish custody for no clear reason".

"We will not stop pushing for a solution and release in these cases as well," Gabriel said.

Steudtner, 46, was arrested by Turkish police on July 5 from a workshop in Istanbul along with nine others.

Of the at least 11 German citizens detained in Turkey, Steudtner is the only one held on political charges in the wake of the failed military coup in Turkey in 2016.

His detention triggered outrage among policymakers in Berlin.

The Istanbul court where Steudtner's trial commenced on Wednesday granted a request by the state attorney to release him along with seven other suspects on bail.

Steudtner is not bound to remain in Turkey until the trial resumes on November 22, and is expected to arrive in Berlin later on Thursday.

During his first 40-minute defence speech in court, he denied the charge that he was a member of a terrorist organization.

If found guilty, he faces up to 15 years in prison.