Nine Ethiopian journalists and bloggers held in detention since April have been charged with terrorism by a court in the capital, Addis Ababa.
They deny receiving financial aid and instructions from terrorists groups to destabilise the country.
New York-based Committee to Protect Journalists (CPJ) said the government was trying to stifle opposition and media freedom in the country.
They all belonged to the social media activist group Zone 9.
Correspondents say Ethiopia has increasingly faced criticism from donors and human rights groups for jailing its critics – many of whom have sought asylum abroad in fear of being arrested and tortured in jail.