NAIROBI, Kenya — For a year now, fighters from Ethiopia’s northern region of Tigray have faced off against Ethiopia’s army largely alone, repulsing their attacks, capturing towns and this week, advancing on the capital, Addis Ababa.
But on Friday, the Tigrayans announced that they were banding together with eight other opposition groups to oust Prime Minister Abiy Ahmed — through political negotiation or military force if necessary — and install a transitional government.
“We are left with one option — changing the situation; otherwise we’ll all be massacred,” said Berhane Gebre-Christos, who formerly served as Ethiopia’s foreign minister, speaking for the Tigrayan rebel group, the Tigray People’s Liberation Front. He spoke on Friday in a news conference at the National Press Club in Washington, joined by representatives from the other groups in the alliance.
He urged a resolution “before Ethiopia implodes and affects the region.”
Ethiopia’s attorney general and justice minister, Gedion Timothewos, dismissed the coalition as a “publicity stunt,” saying that some of the organizations had no traction or support.
“I don’t think it will have that much of an impact,” he said in an online news conference on Friday.
The announcement of the alliance comes just days after the rebels captured two towns about 160 miles northeast of Addis Ababa. Ethiopia declared a state of emergency, asked citizens to pick up arms to defend the capital and rounded up ethnic Tigrayans whom the government accused of sympathizing with the rebels now threatening the capital.
The war began in November 2020, when Mr. Abiy launched an offensive into the restive Tigray region after accusing the Tigray People’s Liberation Front of carrying out a surprise attack on a federal military base. In August, the Tigrayan rebels joined forces with another group, the Oromo Liberation Army; the Ethiopian government has designated both groups as terrorist organizations.
The conflict has convulsed Africa’s second-most populous nation, leaving thousands dead, an estimated two million people displaced and hundreds of thousands facing famine.
The United Nations and the Ethiopian human rights commission published a joint report this week pointing to “appalling levels of brutality” in the war, including extrajudicial killings, sexual violence and attacks on refugees.
Diplomats from the United States, Europe and Africa scrambled to find a negotiated solution. The Ethiopian prime minister met on Friday with Jeffrey Feltman, the American envoy to the Horn of Africa, in an effort to resolve the crisis, and “held constructive discussions,” Billene Seyoum, a government spokeswoman, said in a written response.
The U.S. Embassy in Ethiopia advised American citizens on Friday to leave the country “as soon as possible,” and added that “the security environment in Ethiopia is very fluid.”
But Ms. Seyoum dismissed reports in recent days of an atmosphere of siege in the capital, calling it disinformation.
“The capital is moving about with a sense of normalcy,” she said in the online news conference.
The new alliance, analysts say, adds a measure of political pressure to Mr. Abiy’s woes. He already faces escalating military resistance in divergent pockets of Ethiopia, and the prospect of economic problems as rebels threaten to block a crucial road connecting landlocked Ethiopia to the port in Djibouti to the east.
The alliance’s formation “is another sign that the political tides are changing,” said William Davison, a senior Ethiopia analyst with the International Crisis Group.
In the event that there is a breakdown in the ruling party or a major power shift in Addis Ababa, Mr. Davison said, “these groups could play a key role in their respective strongholds as we move into a new transitional phase.”
But it is unclear how potent the alliance will be. Some of the armed groups “do not have a strong fighting force,” and the political groups “have even weaker political programs.”
Mr. Abiy has drawn much of his support from the Amhara and Oromo ethnic groups. Ethiopia is a patchwork of at least 80 ethnic groups and 10 regional governments, with simmering divisions over land, history, language and the balance of power between federal and regional governments. Besides the Tigrayans, the coalition includes groups representing ethnic Oromos, Somalis, and the Sidama, among others.
The fact that the Tigray People’s Liberation Front is in the forefront of the coalition will likely alienate many Ethiopians. For almost three decades, beginning in 1991, the T.P.L.F. was the dominant political force in Ethiopia, where it muzzled free speech, detained journalists and crushed political dissent. But its influence waned after Mr. Abiy came to power in 2018 promising to distribute power and resources equally. He eventually demoted and marginalized many Tigrayan government officials.
On Friday, protests against the Tigray People’s Liberation Front were held in Addis Ababa and other Ethiopian cities. Mr. Gedion, the attorney general, called the T.P.L.F. “unpopular” and said its members “could not accept an Ethiopia in which they were not the masters of everything.”
Leaders of the new coalition, known as the United Front of Ethiopian Federalist and Confederalist Forces, urged the Biden administration to support their efforts.
“I think the Biden government has to unite with us. They have to stand behind us,” Okok Ojulu Okok, who represents the Gambella People’s Liberation Army, said at the news conference in Washington. “They have to support us, in every direction that we go.”
It was unclear how the Biden administration will regard the new alliance. Jalina Porter, a State Department spokeswoman, declined to comment on the coalition, but said in a briefing on Friday, “We continue to urge all parties to the conflict to end hostilities immediately.”
Abdi Latif Dahir reported from Nairobi, and Lara Jakes from Washington.