At least 54 people have been killed in Ethiopia after rebels attacked three villages.

Human rights group Amnesty International says a group linked to the Oromo Liberation Army attacked the villages in the West Welega Zone late Sunday.

According to Amnesty, the rebels gathered villagers into a school before killing them. They then looted the villages and burned them.

The Ethiopian Human Rights Commission said that the group responsible had about 60 members. It added that the attack happened just a day after government forces had withdrawn from the area.

Ethiopian Prime Minister Abiy Ahmed's efforts to unite the country's ethnically federated states over the past few years have largely been futile. The massacre this past weekend underscores that. Global human rights groups are concerned about the government's ability to prevent similar events.

Since Abiy came into power in 2018, he has introduced changes to subdue ethnic disputes. These include the long-running and violent dispute between the Oromo and Amhara - who represent about 60% of the nation's population of 108 million people.

Some of the changes included the releasing of political prisoners, initiating peace talks with its neighbor Eritrea and legalizing the formation of opposition groups. New parties and groups have emerged to challenge the government's rule.

One of those groups is the Oromo Liberation Army, a group that broke off from the political party the Oromo Liberation Front. Ethiopian authorities have accused it of inciting ethnic tensions with the goal of destabilizing the government.

The group's latest action was its alleged involvement in the killing of a popular Oromo singer in late June. The murder caused nationwide unrest and violence resulting in the deaths of hundreds. It also forced the government to shut down news outlets.