Tigray rebels "massacred innocent people, looted and destroyed various institutions," Afar administration says, while the UN calls for end to fighting which it says is blocking aid to neighbouring Tigray region.
More than 300,000 people have been displaced by warfare in Ethiopia's Afar region since December, the regional adminsitration has said, accusing Tigray rebels of killing civilians and looting.
Officials in the Afar region said in a statement on Monday that the Tigray People's Liberation Front (or TPLF) had invaded that region in December.
"It has massacred innocent people, looted and destroyed various institutions, and displaced more than 300,000 innocent people," the statement said, without giving further details.
It was not immediately possible to reach TPLF spokesperson Getachew Reda on Tuesday for comment.
The Afar statement said Tigrayan rebels were advancing towards a checkpoint at Serdo, on the highway that links landlocked Ethiopia to Djibouti, the region's main port.
Fighting was raging in five districts and in the town of Abala, it said.
The United Nations has said that the fighting in Afar was blocking the delivery of food to neighbouring Tigray region, where several hundred thousand people are living in famine conditions.
"People are fleeing in absolute fear in all directions," said an aid worker in Afar, who asked not to be named.
The aid worker told that one of her colleagues had been killed in the fighting and two were missing.
Her organisation had transported two injured children to get medical treatment, she said. During the journey, a colleague called their mother to tell them the children's father had been killed.
War erupted in Tigray in November 2020, pitting the Ethiopian government and its allies, including Afar troops, against militias loyal to TPLF, which controls the region.
The conflict in northern Ethiopia has killed thousands of civilians and displaced millions across three regions in Ethiopia and into neighbouring Sudan.
UN: humanitarian supplies impossible
The Afar Pastoralist Development Association, a local aid group, supplied pictures of wounded children in Dubti hospital, including a badly burned boy, whose father told aid workers his two sons aged 9 and 11 had been wounded when artillery fire hit their home in the town of Abala on January 15.
The Afar statement did not mention Ethiopian federal government troops.
The aid worker said she did not believe Ethiopian soldiers were involved.
One of the Afar forces told the military was not supporting them against Tigrayan rebels.
Ethiopian military spokesperson Getnet Adane did not respond to a request for comment.
The United Nations says the fighting in Afar has made delivering humanitarian supplies to Tigray by road impossible since December 15.
All international aid groups in Tigray have run out of fuel and are delivering what aid they can on foot, it says.
The UN World Food Programme said last month that nine million people need food aid across Tigray, Afar and Amhara regions as aid groups struggle to reach cut-off areas.
The appointment of Abiy Ahmed as prime minister in 2018 ended 27 years of TPLF dominance over the Addis Abbaba government but the party stayed in power in its home region.
Each side blames the other for provoking the conflict.
The TPLF accuses Abiy of centralising power at the expense of the regions, which he denies, while Abiy accuses the TPLF of seeking to return to power at the national level, which it rejects.