On Friday, a newly formed alliance of Ethiopian groups announced its intention to depose Prime Minister Abiy Ahmed by force or diplomacy and create a transitional administration.

The Ethiopian government denounced the coalition as a publicity ploy, claiming that some of its members were involved in ethnic violence.

Despite calls from African and Western leaders for a cease-fire in the war, which pits the central government against the northern-based Tigray People's Liberation Front (TPLF) and its supporters, faction leaders declared the alliance in Washington.

According to official media, with rebel troops poised to march into Addis Abeba, the Ethiopian army called for former service members to re-enlist to battle them on Friday.

In another indicator of growing international concern, the United States Embassy recommended all American citizens leave Ethiopia as soon as possible.

"The security climate in Ethiopia is quite fluid," according to the embassy.

The alliance seems to be the latest intervention of the United States in the African nation which the UN claims to be on a brink of catastrophe following the crisis of the Native Tigray Nationality.

The year-long conflict has killed thousands of civilians and displaced over two million more. It has gotten worse in recent weeks.

The coalition announced the foundation of the United Front of Ethiopian Federalist and Confederalist Forces at a Washington event, saying it will establish a command to coordinate its military and political activities.