GIJET, Ethiopia — The convoy sped down from the mountain, slipping and sliding on roads greasy from a recent shower of hailstones. As it descended toward the regional capital of Tigray, curling through rocky hills and remote hamlets, people clustered along the route in celebration.
Women stood ululating outside stone farmhouses, and fighters perched atop a ridge fired their weapons into the air as the vehicles curled around the detritus of battle: burned-out tanks, overturned trucks and a mucky field where on June 23 an Ethiopian military cargo plane, shot down by the Tigrayans, had smashed into the ground.
The leader of Tigray, Debretsion Gebremichael, was going home.
Two days earlier, his scrappy guerrilla force had retaken the regional capital, Mekelle, hours after Ethiopian troops suddenly abandoned the city. Now Mr. Debretsion, a former deputy prime minister of Ethiopia, was leaving the mountains where he had been ensconced for eight months leading a war to re-establish his rule over the region.
“I didn’t expect to make it back alive,” Mr. Debretsion said on Thursday night in an interview, his first since the fall of Mekelle. “But this isn’t personal. The most important thing is that my people are free — free from the invaders. They were living in hell, and now they can breathe again.”
Prime Minister Abiy Ahmed ordered a military operation there. The civil war has led to the displacement of nearly two million people, and to widespread hunger and reports that civilians were subjected to atrocities and sexual violence.
Mr. Debretsion, who is believed to be in his late 50s, claimed to have crippled Ethiopia’s powerful army, defeating seven of its 12 divisions and killing at least 18,000 soldiers. He also detailed plans to expand the war across Tigray, in defiance of international calls for a cease-fire, until his fighters have expelled from the region every outside force, including Eritrean soldiers and ethnic Amhara militias.
“They have taken the land by force,” Mr. Debretsion said. “So we will take it back by force.”
Tigray Defense Forces mounted a spectacle that seemed intended to humiliate Ethiopia’s leader. The fighters marched at least 6,000 Ethiopian prisoners of war through downtown Mekelle past residents chanting, “Abiy is a thief!” A woman holding a large photograph of Mr. Debretsion led the procession.
The Tigrayan leader fought his first war in the 1980s as the head of a guerrilla radio station for the Tigray People’s Liberation Front, a rebel group leading the resistance against a brutal Marxist dictatorship in Ethiopia.
The rebels swept to power in 1991, with the Tigrayan leadership at the head of a governing coalition that dominated Ethiopia for nearly three decades until Mr. Abiy became prime minister in 2018.