Prime Minister Hailemariam Desalegn, whose administration denies crushing peaceful opposition, said the move was intended to “foster national reconciliation”.
It follows recent protests over land rights and repression and ethnic clashes, and takes place amid a political crisis that has seen some senior officials submit resignations from the ruling party.
“Politicians currently under prosecution and those previously sentenced will either have their cases annulled or be pardoned,” Hailemariam told domestic news outlets in the capital. He did not give further details.
The Horn of Africa country has been wracked by violence for almost three years, with protests first breaking out in its Oromiya province over allegations of land grabs.
Several dissident politicians have since been jailed having been charged with involvement in terrorism and collusion with the secessionist Oromo Liberation Front, which the government has branded a terrorist group.
Rallies over land rights then broadened into demonstrations over political restrictions and perceived rights abuses, including the incarceration of Merera Gudina and Bekele Gerba — leaders of the opposition group the Oromo Federalist Congress.
ETHNIC CLASHES
Rights group Amnesty International said the decision could signal the “end of an era of bloody repression”.
“A new chapter for human rights will only be possible if all allegations of torture and other ill-treatment are effectively investigated and those responsible brought to justice,” Fisseha Tekle, its researcher on Ethiopia, said in a statement.
In recent months, a spate of ethnic clashes have also taken place. Dozens of people were killed in several bouts of violence between ethnic Oromos and Somalis in the Oromiya region last year.
Hailemariam made his announcement after the ruling EPRDF coalition concluded a weeks-long meeting meant to thrash out policies to address grievances.
The unrest had triggered growing friction within the party. Two high-ranking members subsequently submitted their resignation, while officials have openly squabbled with each other over the cause of clashes.
Ethiopia, sandwiched between volatile Somalia and Sudan, is often accused by rights groups of regularly using security concerns as an excuse to stifle dissent and media freedoms. It denies the charge.
The government in Addis Ababa has been denying imposing political restrictions.
Hailemariam said a detention facility known as “Makelawi”, where rights groups have alleged that torture has taken place, would also be closed down and turned into a museum.
Reporting by Aaron Maasho; Editing by Catherine Evans, William Maclean