Writers, cartoonists and executives were facing up to 43 years in jail on Monday for allegedly supporting three groups labeled terror outfits by Turkey. 

Several hundred supporters of the secularist Cumhuriyet newspaper crammed into the Istanbul courtroom as the trial opened and applauded the defendants. They released dozens of multicolored balloons outside the courthouse, chanting: "Don't be silenced! A free media is a right!"

Read more: Turkish newspaper Cumhuriyet faces nebulous accusations in trial

Some of Turkey's most well-known journalists were among the defendants, including the columnist Kadri Gursel, the paper's editor-in-chief Murat Sabuncu, cartoonist Musa Kart as well as its chairman Akin Atalay. Most of the 17 defendants had been in jail without charge for the past eight months.

Also on trial was former editor Can Dundar, who is living in Germany, and is being tried in absentia.

"I am not here because I knowingly and willingly helped a terrorist organization, but because I am an independent, questioning and critical journalist," columnist Gursel told the court.

Three alleged terror groups

They stand accused of supporting the Kurdistan Workers' Party (PKK), the ultra-left Revolutionary People's Liberation Party-Front (DHKP-C) and the movement of US-based cleric Fethullah Gulen, which Ankara calls the Fethullah Terror Organization (FETO) and blamed for the failed coup last July.

Prosecutors alleged Cumhuriyet was taken over by Gulen's network and used to "veil the actions of terrorist groups". Gulen has denied any involvement in the coup.

They also accused the newspaper of writing stories that served "separatist manipulation."

Gursel denied he had links to Gulen's movement, saying he had in the past revealed ties between Erdogan's AK Party and the Gulen movement. Once close friends, Gulen and Erdogan had a public falling out in 2013.

Biggest press freedom trial in Turkey

Digital rights activist and professor at the law faculty at Istanbul's Bilgi University, Yaman Akdeniz, said it was one of the biggest freedom of speech and press related trials to happen in Istanbul.

"This will be one of the most important cases in relation to (the) July 15 coup attempt. I believe personally, from what I've seen in the dossier so far, that there is nothing to detain and keep all these journalists arrested," Akdeniz told DW.

"We are extremely concerned about this case," Steven Ellis, Director of Advocacy and Communications at the International Press Institute (IPI) told DW. "We think that this case is an emblematic of really what is happening in journalism in Turkey. Journalism is being criminalized, politically motivated charges are being brought to try and silence the critics of this government."

Some 150 outlets shut down

Since the July coup attempt, more than 50,000 people have been arrested pending trial and 150,000 people have been detained or dismissed from their jobs. About 150 media outlets were also shut down and about 160 journalists have been jailed, according to the Turkish Journalists' Association. Even before the post-coup crackdown, Turkey regularly featured near the top of annual league tables tracking the number of imprisoned journalists around the world.

Reporters Without Borders told DW that Turkey had become a systematic violator of the rule of law and that this case showed it had little regard for its own citizens.

Cumhuriyet has continued publishing the columns of the jailed journalists but with a blank white space instead of text.

Press freedom day

The start of the trial coincided with Turkey's annual national day of the press, which celebrates the end of official censorship in the Ottoman Empire in 1908.

Former editor Dundar said it was a sad irony the two dates coincided, in a Berlin interview with the Associated Press.

"We are defending our news [reports], our articles, our tweets - nothing else," he said. "It's a case about journalism not terrorism," said Dundar, who now runs a bilingual news website critical of Turkey's government in Berlin.

On Monday Turkey withdrew a controversial blacklist of German companies it accused of supporting terrorism.Read more: Turkey drops terrorism claims against German firms

Read more: Germany overhauls Turkey policy

Mahmut Tanal, deputy leader of the opposition Republican People's Party (CHP) said it was clearly a political trial rather than a legal process.

"The editorial policy of a newspaper has never been the subject of a hearing in any other country in the world up until now. It shouldn't be so in democratic countries,"  he told DW.

aw/msh(AFP, Reuters, AP)