Ethiopia, sandwiched between war-torn South Sudan and Somalia, is frequently rebuked by human rights groups for cracking down on dissent under the guise of national security concerns.
The government rejects the accusations.
Since 2015, hundreds of people have been killed in the country’s largest province, Oromia, and to a lesser extent in Amhara, as protests broadened into demonstrations against political restrictions and human rights abuses.
Mr. Nega, a blogger and journalist, was arrested in 2011 and accused of trying to incite violence with a series of online articles. He was sentenced to 18 years.
In the same case, Mr. Arage, a member of the opposition Unity for Democracy and Justice party, was sentenced to life imprisonment.
Both were among a group of 20 people on trial. Among the others were five exiled journalists who were sentenced in absentia to prison terms of 15 years to life.
It was not immediately clear whether the other members of that group were being pardoned.