They were transferred to a federal prison in June, and charged with secretly organizing to destabilize the government and working with the outlawed Ginbot 7 and Oromo Liberation Front groups.
The charges, under a sweeping 2009 anti-terrorism law, were brought to the Federal High Court in Addis Ababa. The nine suspects were jailed in May. The bloggers are members of a dissident group called Zone 9 and writers on an anti-government website called "the Dissident Blog."
The defendants' lawyer, Ameha Mekonnen, called the charges vague, saying, "If you read the text between the lines, it doesn't make any sense. It's nonsense."
Ethiopian Prime Minister Hailemariam Desalegn disagreed Friday, saying, "I don't think becoming a blogger makes somebody immune, if someone involves into this terrorist network that destabilizes my country."