The human rights organization Amnesty International has called on Ethiopia to release detained opposition leaders, journalists and human rights defenders set to go on trial Thursday.
The group of more than 80 defendants face charges that include treason and genocide, which carry a maximum sentence of the death penalty.
In a statement Wednesday, Amnesty said the defendants were imprisoned "solely on account of their non-violent opinions and activities."
The rights group accused the Ethiopian government of trying to criminalize freedom of expression and prevent legitimate political and human rights activity.
The defendants were arrested following violent anti-government riots late last year.
More than 40 other people charged are outside the country and may be tried in absentia. That group includes five Voice of America journalists in Washington who have worked with VOA's Amharic-language service.