The controversial trial of two well-known Turkish journalists enters its second day Friday in a case seen as a test of press freedom under the increasingly autocratic President Recep Tayyip Erdogan.

The controversial trial of two well-known Turkish journalists enters its second day Friday in a case seen as a test of press freedom under the increasingly autocratic President Recep Tayyip Erdogan.

Can Dundar, editor-in-chief of leading opposition daily Cumhuriyet, and Erdem Gul, his Ankara bureau chief, are charged with espionage and revealing state secrets over a story accusing the government of seeking to illicitly deliver arms to Syria insurgents.

The pair could face life in prison, but a defiant Dundar voiced optimism they would be found not guilty as he arrived at the Istanbul criminal court.

"We will win. We have always won throughout history. We think the laws will show we are right and we will be acquitted," Dundar told reporters.

"It's journalism that is on trial here. This trial should not be taking place," added Gul.

As on the first day of the proceedings -- which opened March 25 -- the case was going on behind closed doors.

On the first day of the trial, the court granted a prosecution request to hold the hearings in secret. Prosecutors cited "national security" concerns.

That decision was met with cries of dismay inside the courtroom and opposition politicians refused to leave, prompting the judge to adjourn the trial to April 1.

Reporters Without Borders ranked Turkey 149th out of 180 countries for press freedom in 2015 over the widening clampdown on critics of the president and the state's bloody war with militants from the outlawed Kurdistan Workers' Party.

In a separate incident in Washington on Thursday, Erdogan's security detail clashed with the press ahead of the president's speech at the Brookings Institute in the US capital.

One of the guards aimed a chest-high kick at an American reporter attempting to film the harassment of a Turkish opposition reporter.

Turkish security also tried to prevent two Turkish journalists -- one of them working for the opposition daily Zaman that has been seized by the government -- from entering.

That sparked tense scenes with staff from Brookings, who had invited the reporters to cover the event.