A resident of the disputed land in Ethiopia’s Tigray. [Picture, Standard]

The dusty buses keep coming, dozens a day, mattresses, chairs and baskets piled on top. They stop at schools hurriedly turned into camps, disgorging families who describe fleeing from ethnic Amhara militia in Ethiopia's Tigray region.

Four months after the Ethiopian government declared victory over the rebellious Tigray People's Liberation Front (TPLF), tens of thousands of Tigrayans are again being driven from their homes.

This time, it is due not to the fighting, but to regional forces and militiamen from neighbouring Amhara seeking to settle a decades-old land dispute, according to witnesses, aid workers and members of Tigray's new administration.

Amhara officials say the disputed lands, equal to about a quarter of Tigray, were taken during the nearly three decades that the TPLF dominated central government before Prime Minister Abiy Ahmed came to power in 2018.

"The land belongs to the Amhara region," Gizachew Muluneh, spokesman for the Amhara regional administration, told Reuters.

Ababu Negash, 70, said she fled Adebay, a town in western Tigray, after Amhara officials summoned Tigrayans to meetings in February.

"They said you guys don't belong here," Ababu told Reuters in Shire, a town 160km to the east, to where many from west Tigray are fleeing. "They said if we stay, they will kill us."

This fresh exodus from the west of Tigray risks exacerbating a precarious humanitarian situation in the region, with hundreds of thousands of people already uprooted by fighting. The territorial dispute is also being carefully watched by other regions in Ethiopia's fractious federation, some with their simmering border disputes.

Fighters from Amhara entered western Tigray in support of federal forces after the TPLF, Tigray's then-governing party, attacked military bases there in November. They have remained ever since, and Amhara officials say they have taken back a swathe of territory that was historically theirs.

Tigrayan officials say the area has long been home to both ethnic groups and that the region's borders are set by the constitution. Now that fighting has subsided and roads have reopened, they say there is a concerted, illegal push to drive out Tigrayans.

Reuters interviewed 42 Tigrayans who described attacks, looting and threats by Amhara gunmen. Two bore scars they said were from shootings.

"The western Tigray zone is occupied by the Amhara militias and special forces, and they are forcing the people to leave their homes," Mulu Nega, head of Tigray's government-appointed administration, told Reuters in Tigray's capital Mekelle.

He accused Amhara of exploiting Tigray's weakness to annex territory. "Those who are committing this crime should be held accountable," he said.

Asked about the accounts of violence and intimidation by Amhara fighters, Yabsira Eshetie, the administrator of the disputed zone, said nobody had been threatened and only criminals had been detained.

"No one was kicking them out, no one was destroying their houses even. Even the houses are still there. They can come back," he said. "There is federal police here, there is Amhara special police here. It is lawful here."

Reuters was unable to reach Amhara police, and federal police referred questions to regional authorities.

Gizachew said Amhara was now administering the contested territory, reorganising schools, police and militia, and providing food and shelter. Tigrayans were welcome to stay, he said, adding that Amhara has asked the federal government to rule on the dispute and expected a decision in coming months.

He did not respond to requests for comment on the accusations of violence and intimidation by Amhara fighters.

The prime minister's office referred Reuters to regional authorities to answer questions about the land dispute and the displacement of Tigrayans, who make up around five per cent of Ethiopia’s 110 million people. There was no response from a government task force on Tigray or the military spokesman.

In a speech to parliament on March 23, Abiy defended Amhara regional forces for their role in supporting the government against the TPLF. "Portraying this force as a looter and conqueror is very wrong," he said.

The United Nations has warned of possible war crimes in Tigray. US Secretary of State Antony Blinken said this month there have been acts of ethnic cleansing.