Abiy's Prosperity Party, a pan-Ethiopian movement he founded a year ago, faces challenges from increasingly strident ethnically-based parties seeking more power for their regions.

Africa's second most populous nation has a federal system with 10 regional governments, many of which have boundary disputes with neighbouring areas or face low-level unrest.

In the northern Tigray region, thousands of people are believed to have died and 950,000 have fled their homes since fighting between regional and federal forces erupted on November 4.

Tigray held its own elections in September in defiance of the federal government, which declared the polls illegal.

The National Electoral Board said next year's calendar for polls did not include an election in Tigray. It said the date for a Tigray vote would be set once an interim government, which was established during the conflict, opened election offices.

The national vote was postponed from August this year due to the coronavirus crisis. The head of the winning party becomes prime minister.

For nearly three decades until Abiy's appointment, Ethiopia was ruled by a coalition of four ethnically-based movements dominated by the party from Tigray. That administration ruled in an increasingly autocratic fashion until Abiy took power in 2018 following years of bloody anti-government street protests.

The initial months after Abiy's appointment saw a rush of political and economic reforms, including the release of tens of thousands of political prisoners.

Abiy merged three of the main regional parties last year to form the Prosperity Party. The fourth, the Tigray People's Liberation Front (TPLF), refused to join.

Voter registration for the June vote would take place from March 1 to 30, the electoral board said.

Abiy's peace deal with Eritrea, which won independence from Ethiopia in 1993 after years of conflict, helped earn him the Nobel Peace Prize in 2019. But his moves to loosen the Ethiopian government's iron grip was followed by outbreaks of violence as regional politicians and groups jostled for resources and power.

Abiy ordered troops to the western Benishangul-Gumuz region, which borders Sudan, on Thursday after attackers torched homes and killed more than 200 people in a village.

The prime minister is also grappling with a long-running insurgency in Ethiopia's most populous region Oromiya.

The opposition Oromo Liberation Front, deemed a terrorist movement until Abiy lifted a ban on the group, had said on December 12 that the government wanted to hold elections to divert attention from Ethiopia's security problems.

Many Oromo politicians are in jail, such as Jawar Mohammed, a prominent media mogul and member of the Oromo Federalist Congress party.

He and other party leaders were charged in September with terrorism offences after the killing of popular Oromo musician Haacaaluu Hundeessaa, whose death sparked protests that killed at least 178 people in Oromiya and the capital Addis Ababa.

Australian Associated Press