ISTANBUL (Reuters) - Hundreds of people including opposition politicians protested outside the trial of two prominent Turkish journalists facing life in prison on espionage charges on Friday, hours after President Tayyip Erdogan denied curbing press freedoms.

Can Dundar, editor-in-chief of Cumhuriyet (L), accompanied by his Ankara bureau chief Erdem Gul, arrives at the Justice Palace for his trial in Istanbul, Turkey April 1, 2016. REUTERS/Osman Orsal

Can Dundar, editor-in-chief of the Cumhuriyet newspaper, and Ankara bureau chief Erdem Gul are accused of trying to topple the government with the publication last May of a video purporting to show Turkey's state intelligence agency helping to ferry weapons into Syria by truck in 2014.

Their case has brought international condemnation and raised concerns about freedom of expression in Turkey. At their first hearing a week ago, the court took the case behind closed doors and accepted Erdogan as a complainant in what critics said was a move that undermined judicial independence.

"During the legal process, the president personally intervened, both as a complainant and through his repeated public statements. Turkey's judicial system is not strong enough to shrug off the dominance of this president," Muharrem Ozay, a lawyer for the two journalists, told Reuters.

Erdogan has cast the newspaper's coverage as part of an attempt to undermine Turkey's global standing and has vowed that Dundar will "pay a heavy price".

He 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.

Ali Seker, one of more than a dozen opposition members of parliament outside the court room, said he and his colleagues were trying to exercise their legal right to observe the case and were concerned that Gul and Dundar might be re-arrested.

The court on Friday rejected the opposition applications, lawyers said. Supporters chanted "You cannot silence the free press" and "Shoulder to shoulder against fascism".

The two journalists 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 and they were released.

Erdogan said he did not respect that ruling.

INTERNATIONAL CONCERN

The trial comes as Turkey tries to deflect criticism from the European Union, United States and rights groups that say it is bridling a once-vibrant press.

There were ugly scenes in Washington on Thursday, where Erdogan is on a visit, as his bodyguards tried to stop protesters chanting and waving banners outside the Brookings Institution think-tank where he was speaking.

"Turkey's leader and his security team are guests in the United States," said Thomas Burr, president of the National Press Club. "They have no right to lay their hands on reporters or protesters or anyone else for that matter ... Erdogan doesn't get to export such abuse."

In his speech at Brookings, Erdogan warned he would continue to sue critics who insult him in Turkey, while in an interview with CNN, he denied being "at war" with the press.

"Espionage, do you think it is a freedom of expression or a freedom of press?" he told the broadcaster.

Ahead of the trial, Dundar told Reuters he would use the hearings to refocus attention on the story that landed him in the dock, describing himself as a witness not a defendant.

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

The prosecutors have denied those allegations, while Gulen has denied plotting against the government.