Ethiopia's Somali region says a vital road and rail trade route linking the landlocked capital of Addis Ababa to the sea port of Djibouti has been blocked by youths angered by a deadly militia attack on their region.
About 95 per cent of imports into the country of around 110 million people are transported via that corridor, according to a 2018 study by the UN Conference on Trade and Development.
Reuters could not independently verify the reported blockage.
The Ethiopian prime minister's office and authorities in Djibouti could not immediately be reached for comment.
Somali region President Mustafa Muhumed Omer said the road and railway had been blocked by youths protesting against an attack on the region's Gedamaytu town by militia from the neighbouring region of Afar.
A spokesman for his administration said Saturday's attack had caused hundreds of civilian deaths and the town had been looted and many of its inhabitants displaced.
The violence is the latest flare-up in a local boundary dispute that adds to high tensions in the Horn of Africa country.
Reuters was unable independently to verify the report of hundreds killed and Afar's government did not immediately respond to a request for comment.
A 30-year-old resident of the Somali region's capital Jigjiga, who only gave his name as Hassan for security reasons, said thousands took the streets on Wednesday to protest against the killing of Somalis on Saturday.
He said protesters were holding banners written in Amharic and Somali, one reading "children didn't deserve to be slaughtered".
Local journalist Najib Dayib, director of the privately owned Ogedenia Media Agency, earlier told Reuters protesters numbered in the hundreds.
Reuters was unable to independently verify the demonstration but viewed footage and images of the protest that indicated many hundreds had gathered.
"We are working to open the Djibouti rail and road today," Mustafa, the Somali region president, told Reuters in a text message.
"Discussing with the youth and people," he added.
After Ethiopian Prime Minister Abiy Ahmed took office in 2018 and eased the ruling coalition's iron grip, the country experienced a surge in violence as regions and ethnic groups vied for more power and resources and tried to settle old scores.
Abiy's government has struggled to contain fighting along a number of contested border areas between ethnic groups, including the fault-line where Saturday's attack occurred.
The most deadly violence, however, has been in the Tigray region.
In November, a war broke out between Ethiopia's central government and the Tigray People's Liberation Front (TPLF), the party that controls Tigray.
Last week, it spread to neighbouring parts of northern Ethiopia, risking a further destabilisation of the country.
Abiy's spokesperson told a news briefing in the capital on Wednesday that the lives of people in the Afar and Amhara regions "are being destabilised by the terrorist enterprise," referring to the Tigrayan fighters.
Australian Associated Press