Hundreds of protesters gathered outside the Istanbul office of an opposition newspaper Friday, accusing the government of silencing critics and attempting to coverup a scandal after two journalists were jailed on terror and espionage charges for their reports on alleged Turkish arms smuggling to Syria.
Cumhuriyet newspaper's editor-in-chief Can Dundar and the paper's Ankara representative Erdem Gul, were sent to a prison in Istanbul late on Thursday, accused of willingly aiding a terror organization and revealing state secrets.
The incident comes amid deepening concerns over media freedoms in Turkey, which aspires to join the European Union.
In May, the paper published what it said were images of Turkish trucks carrying ammunition to Syrian militants.
The images reportedly date back to January 2014, when local authorities searched Syria-bound trucks, touching off a standoff with Turkish intelligence officials. Cumhuriyet said the images were proof that Turkey was smuggling arms to rebels in Syria.
The government had initially denied the trucks were carrying arms, maintaining that the cargo consisted of humanitarian aid. However, some officials later suggested that the trucks were in fact carrying arms or ammunition destined to Turkmen in Syria.
Prosecutors launched an investigation into the journalists after President Recep Tayyip Erdogan filed a criminal complaint.
Crowds filled the yard and a street outside of Cumhuriyet's headquarters, chanting: "Free press cannot be silenced."
Opposition legislator Baris Yarkadas said: "The government does not want any journalist to see what kind of a calamity they have involved Turkey in."
Mark C. Toner, deputy U.S. State Department spokesman, said in a statement that the U.S. is troubled by the arrests.
"The investigation, criminal charges, and arrest raise serious concerns about the Turkish government's commitment to the fundamental principle of media freedom," the statement said. "These events are only the latest in a series of judicial and law enforcement actions taken under questionable circumstances against Turkish media outlets critical of the government."
At a separate protest in Ankara, police used tear gas to break up a gathering of journalists hoping to march to Cumhuriyet's office in the city.
The U.S. Embassy expressed concern over the arrests of Dundar and Erdem and at the apparent pressure being exerted on Cumhuriyet.
"We hope the Turkish courts and authorities will uphold the fundamental principle of media freedom enshrined in the Turkish Constitution," the Embassy said on Twitter.