Merera Gudina, leader of the Oromo Federalist Congress from the Oromiya region which was the center of protests against land grabs, was arrested in November after returning from meeting members of the European Parliament in Brussels.
On Friday, prosecutors formally charged Merera with a bid to “dismantle or disrupt social, economic and political activity for political, religious and ideological aim … under the guise of political party leadership,” according to a charge sheet brought before a high court in Addis Ababa.
Merera was also accused of backing a terrorist group and flouting guidelines of a state of emergency imposed in October during his trip to Belgium.
Two other dissidents were also charged with similar accusations in absentia.
Last week, Human Rights Watch criticized the move to arrest Merera.
“Instead of taking actions that would demonstrate genuine resolve to address long-term grievances, the government again used politically motivated charges to further crack down on opposition parties, reinforcing a message that it will not tolerate peaceful dissent,” the U.S.-based watchdog said.
More than 500 people were killed in protests in the Oromiya region that stretched for months until the government declared a six-month state of emergency in October.
The demonstrations were initially triggered by anger over a development scheme for the capital that demonstrators said would force farmers off their land, but then broadened into demonstrations against political restrictions.
Businesses in Oromiya and other areas, many of them foreign-owned, were attacked. Foreign firms have often been leased land by the government that locals say was seized from them for little compensation and sold on at great profit.