It was the second time Prime Minister Abiy Ahmed's government and the OLA had sat down this year aiming to end a five-year insurgency in the restive Oromia region.

Classified as a "terrorist organisation" by Addis Ababa, the OLA has been fighting the government since 2018 after splitting from the Oromo Liberation Front (OLF) when it renounced armed struggle.

"Due to the intransigence of the other party the talks have come to an end without an agreement," Abiy's national security adviser Redwan Hussein posted on X, formerly Twitter.

"The obstructive approach and unrealistic demands of the other party are the principal reasons why these talks could not succeed."

There was no immediate comment from the OLA.

A diplomat told AFP in early November that both parties were optimistic about the talks taking place in the Tanzanian capital Dar es Salaam.

The OLA had stated on November 13 that its leader, Jaal Maroo, was in Tanzania to lead the talks, and had expressed its determination to achieve a "peaceful political settlement".

An earlier round of talks between April and May also ended without agreement.

Abiy is of Oromo descent but the wider community, Ethiopia's largest ethnic group, has long complained of marginalisation and their homeland is plagued by instability and armed violence.

Since the OLA broke off and started fighting, a string of armed groups have risen up in Oromia claiming to be part of its cause, although they are only loosely tied.

The OLA's strength, estimated at a few thousand men in 2018, has increased significantly in recent years, though observers believe it is insufficiently organised or well-armed to pose a real threat to the government.

Oromia, which surrounds the capital Addis Ababa, has suffered ethnic massacres in recent years carried out by unknown groups, particularly in the Qellem Wollega and West Wollega areas.

The OLA has been repeatedly accused by Abiy's government of being responsible for the killings, a charge it denies.

The government in turn is accused of waging an indiscriminate crackdown that has fuelled Oromo resentment against the central government.