ISTANBUL: One of two prominent Turkish journalists facing life in prison on charges of espionage vowed to make the trial, which begins on Friday, a prosecution of official wrongdoing.

Can Dundar, editor-in-chief of Cumhuriyet, told Reuters he would use his trial, which has drawn international condemnation, to refocus attention on the story that landed him in the dock.

Dundar (54) and Erdem Gul (49) Cumhuriyet's Ankara bureau chief, stand accused of trying to topple the government with the publication last May of video purporting to show Turkey's state intelligence agency helping to truck weapons to Syria in 2014.

"We are not defendants, we are witnesses," Dundar said in an interview at his office, promising to show the footage in court despite a ban and at the risk that judges could order the hearings to be held behind closed doors.

"We will lay out all of the illegalities and make this a political prosecution ... The state was caught in a criminal act and it is doing all that it can to cover it up."

Dundar and Gul spent 92 days in jail, almost half of it in solitary confinement, before the constitutional court ruled last month that pre-trial detention was unfounded because the charges stemmed from their journalism.

Both were subsequently released pending trial, though Turkish President Tayyip Erdogan said he did not respect the ruling.

Opposition politicians, fellow journalists and several European diplomats were outside the Istanbul courthouse as Dundar arrived on Friday. Some in the crowd chanted "free press cannot be silenced".

"Today we came here to defend journalism," Dundar said as he entered the building.

Erdogan has acknowledged that the trucks, which were stopped by gendarmerie and police officers en route to the Syrian border, belonged to the MIT intelligence agency and said they were carrying aid to Turkmens in Syria. Turkmen fighters are battling both Syrian President Bashar al-Assad and Islamic State.

Erdogan has said that prosecutors had no authority to order the trucks be searched and that they were part of what he calls a "parallel state" run by his ally-turned-foe Fethullah Gulen, a United States-based Islamic cleric who Erdogan says is bent on discrediting him and the Turkish government.

"HEAVY PRICE"

The trial comes as Turkey deflects criticism from the European Union and rights groups that say it is bridling a once-vibrant press.

"Elsewhere in the world (Dundar and Gul) would be lauded for their efforts to dig into this issue," said Nina Ognianova of the Committee to Protect Journalists (CPJ).

"They have done their jobs as investigative journalists, serving the public interest in pursuing a story that is significant not just for the country, but the region."

Erdogan has cast the newspaper's coverage as part of an attempt to undermine Turkey's global standing and has vowed that Can Dundar would "pay a heavy price". A 473-page indictment says the editors aided a "terrorist" network led by Gulen.

The CPJ's Ognianova said that the trial is part of a "massive crackdown on press freedom", blaming courts' loose reading of terrorism laws and a government hostile to the press.

Authorities this month seized control of Zaman, Turkey's top-selling newspaper, on charges that it funded Gulen's network. A few weeks earlier the pro-Kurdish IMC channel was pulled off the air over allegations of "spreading terrorist propaganda".

Dundar took the helm at Cumhuriyet, which has a circulation of 52,000, last year and worked to overhaul the staunchly secular 92-year-old daily into a left-leaning outlet with more readers.

A new investigative reporting unit he set up unearthed the footage of the purported arms shipment.

Now he faces death threats, an armed guard prowls Cumhuriyet's perimeter and a bomb-suppression blanket sits at the entrance. Photos of potential attackers hang on the wall.

"We knew the risks of publishing this. If you do journalism in Turkey, you know what can happen with dangerous topics," Dundar said in the interview.

"We were arrested for two reasons: to punish us and to frighten others. And we see the intimidation has been effective. Fear dominates. But we actually think we have frightened (the state). Their threats stem from that fear."