An estimated 40,000 to 50,000 fighters are currently in the northern Tigray region as the conflict continues to escalate.
Ethiopia’s military is fighting battle-hardened troops in the northern Tigray region, threatening the stability of the entire Horn of Africa region.
Here are some facts on the forces on the ground:
The national military: The ENDF
The Ethiopian National Defence Force (ENDF) has about 140,000 active personnel, the vast majority in the army, according to the Janes security data group.
Its troops have been tested by armed groups in Somalia and fighters in Ethiopia’s border regions, as well as a two-year border war with Eritrea followed by an 18-year standoff that only ended in 2018.
Between the ENDF forces and other fighters loyal to the federal government, there are an estimated 40,000-50,000 fighters in Tigray at the moment, two diplomats following the conflict said.
Its air force gives it dominance in the skies over Tigray. According to Janes, it has 15 Sukhoi Su-27SK and eight MiG-23ML fighter jets, about 20 Mi-24 and Mi-35 helicopter gunships, and a range of air defence and missile systems, as well as many Russian T-55 and T-72 tanks.
A senior diplomat working on the Ethiopia crisis said Prime Minister Abiy Ahmed had increasingly fallen back on support from forces from Tigray’s southern neighbour Amhara in ground fighting – raising the risk of ethnic violence.
The Northern Command
One big question mark lies over the fate of the firepower and personnel of the federal military’s powerful Northern Command, based in Tigray’s capital Mekelle.
Regional fighters control the headquarters building and have seized heavy weapons, according to a United Nations report.
The northern region’s governing Tigray People’s Liberation Front (TPLF) says it has taken over the Northern Command’s assets. The federal military has acknowledged the loss of a compound but said its troops remain loyal and have been fighting back.
Dozens of ENDF soldiers in the Northern Command remain in their barracks and are taking no part in the fighting, a regional security expert said.
Tigray’s forces: The TPLF
As many as 250,000 soldiers and militia serve under regional commanders in Tigray, according to the International Crisis Group. Of these, there are some 30,000-60,000 effective fighters.
The TPLF says its air defence systems have shot down a federal army jet, an assertion dismissed by the military.
Analysts say they do not yet know what missiles the TPLF used in the attacks on Asmara and targets within Ethiopia but Janes said Tigray had several S-75 and S-125 surface-to-air missile systems.
The regional force has a formidable history. Tigrayan fighters led the rebel march to drive out the Marxist Derg regime in 1991 and bore the brunt of the Eritrean war.
The wild card: Eritrea
Over Tigray’s northern border, Eritrea’s President Isaias Afwerki – a longtime foe of the TPLF – controls a vast standing army the CIA puts at 200,000 personnel.
His government has dismissed TPLF reports that Eritrean troops have already crossed the border, an assertion two diplomats said was highly probable. Any such intervention could tip the Tigray fighting into a regional war.
The TPLF has also accused the federal government of being supported by “non-African actors”, a reference diplomats said was to potential help from the United Arab Emirates, which has a military base at Assab, an Eritrean port on the Red Sea. The UAE has in recent years turned Assab into a strategic hub for its military operations in Yemen.