Two Turkish journalists are standing trial on allegations that they revealed state secrets and helped a terror organization with their reports on alleged government arms smuggling to Syrian rebels.

Cumhuriyet newspaper's chief editor, Can Dundar, and Ankara representative Erdem Gul, face life imprisonment if found guilty of charges of espionage and aiding a moderate Islamic movement led by U.S.-based cleric Fethullah Gulen, a foe of President Recep Tayyip Erdogan.

The pair are on trial for publishing images that reportedly date back to January 2014 when local authorities searched Syria-bound trucks that led to a standoff with Turkish intelligence officials. Cumhuriyet said the images proved Turkey was smuggling arms.

International media advocacy groups, concerned over media freedoms in the country, are pressing Turkey to drop charges. The trial begins Friday.