As tensions rose between Mr. Abiy and the T.P.L.F., Mr. Isaias saw an opportunity to settle old scores and to reassert himself in the region, said Martin Plaut, author of “Understanding Eritrea” and a senior research fellow at the University of London.
“It’s typical Isaias,” said Mr. Plaut. “He seeks to project power in ways that are completely unimaginable for the leader of such a small country.”
Aid groups warn that, without immediate access, Tigray will soon face a humanitarian disaster. The war erupted just as villagers were preparing to harvest their crops, in a region already grappling with swarms of locusts and recurring drought.
Refugees are especially vulnerable. According to the United Nations, 96,000 Eritrean refugees were in Tigray at the start of the fight, although some camps have since emptied. An internal U.N. report from Dec. 12, seen by The Times, described the situation at Hitsats as “extremely dire,” with no food or water.
Farther north at Shimelba camp, Eritrean soldiers beat refugees, tied their hands and left them under the sun all day, said Efrem, a resident who later fled to Addis Ababa, the Ethiopian capital.
“They poured milk on their bodies so they would be swarmed with flies,” he said.
Later, Efrem said, the soldiers rounded up 40 refugees and forced them to travel back across the border, to Eritrea.
Declan Walsh reported from Nairobi, Kenya, and Simon Marks from Addis Ababa, Ethiopia. Lara Jakes contributed reporting from Washington, and Christiaan Triebert from New York.