Two journalists of Turkish left-wing newspaper Cumhuriyet are being tried on charges of terrorist support, as court proceedings began Wednesday in the absence of one of the plaintiffs, former editor Can Dundar.
Along with Erdem Gul, the paper's bureau chief in Ankara, Dundar is accused of "intentionally supporting an armed terrorist organization." Dundar left Turkey in July.
The prosecution has demanded a sentence of 10 years for both Dundar and Gul, according to defence lawyer Bulent Utku.
Gul was in Istanbul to take part in court proceedings, which are off-limits to the public.
Gul and Dundar were sentenced to five years in prison after being found guilty of revealing state secrets. The charges were connected to a report they published last year about alleged arms shipments from Turkey to Syria.
Both actions against them centre around a Cumhuriyet article that reported it had evidence that Turkey's secret service had arranged in early 2014 for weapons shipments across the border to aid Islamist rebels fighting to oust Syrian President Bashar al-Assad.
Although Ankara has repeatedly called for al-Assad's removal, it denies arming rebel fighters.
Turkey ranks 161 out of 180 countries in the Reporters Without Borders Press Freedom Index.
Speaking to dpa on Wednesday, Gul said that the trial had put journalism in the dock: "Reporting has become a crime."
The journalist said that criticism is no longer tolerated in Turkey. The government in Ankara has become increasingly authoritarian in recent months, particularly since a failed coup attempt in July prompted a broad purge of the country's state institutions and media.
"[I]n a country in which more than a hundred journalists are in jail, a record has been broken. It shows that there is no real freedom of speech or free press in Turkey," Gul said.
"But we will continue this fight," he added.
Dundar vowed not to return to his home country due to the wave of detainments following the coup. He is currently residing somewhere in Europe.
The prosecution service has accused the two journalists of having links to Fetullah Gulen, the Islamic preacher who Ankara says was behind the putsch.
Dundar's wife, Dilek Dundar, attended the first day of the trial.
She had her passport confiscated earlier this month on trying to leave Istanbul for Berlin. Dundar at the time accused the government of taking his wife as a "hostage."