ANKARA (Reuters) - A German journalist went on trial for terrorism charges in Turkey on Wednesday, saying she was innocent and demanding her immediate release, in a case that has damaged already sour relations with Berlin.

FILE PHOTO: A supporter of Turkish President Tayyip Erdogan waves a Turkish flag during a pro-government protest in Cologne, Germany July 31, 2016. REUTERS/Vincent Kessler

Mesale Tolu was detained in April, accused of being a member of a terrorist organization and publishing terrorist propaganda. Her husband was also detained and their three-year-old son has been living with his mother in jail for the last five months.

Tolu is one of 18 people on trial accused of membership of the MLKP, a communist party with links to armed Kurdish groups. They face up to 20 years in jail.

“I have not committed any of the above mentioned crimes and have no connection with illegal organizations. I demand my release and my acquittal,” Tolu told the court in Silivri, near Istanbul, Turkish media reported.

The court ordered that Tolu and five other defendants remain in jail pending trial, while releasing eight others. The next hearing will be on Dec. 18.

German Foreign Minister Sigmar Gabriel demanded her release.

“We demand a fair trial, based on the rule of law. Above all, what matters now is speed so that Mesale Tolu can be released as soon as possible,” he told Bild newspaper in an interview published on Wednesday.

Tolu is one of 11 German nationals detained in Turkey - among them fellow journalist Deniz Yucel and human rights campaigner Peter Steudtner.

The cases have added to strains in bilateral relations after Ankara denied German lawmakers permission to visit German soldiers serving at the Incirlik air base.

In a crackdown on alleged perpetrators of an attempted coup last year, some 50,000 people been jailed pending trial.

Chancellor Angela Merkel said last month that Turkey’s 12-year journey to join the European Union should be halted.

Tolu said it was unacceptable that she and her son had spent five months in jail.

“Pre-trial detention has become punishment not only for me but also for my family and for my son,” she told the court.