Forces in Ethiopia's northern Tigray region have clashed with the Eritrean army along the border, a credible source in Addis Ababa has told the BBC.
The source added that the clashes happened in the Tigrayan area of Rama, and the disputed town of Badme, which an international tribunal has awarded to Eritrea. Both sides engaged in shelling using heavy artillery, the source said.
Other sources in Tigray also said there had been fighting at the border.
"Tigrayan forces retreated and the fight halted last night. However, it demonstrates the TPLF's aggressive behaviour," the source said, referring to the Tigray People's Liberation Front, which is in control of the region. It has been fighting Ethiopian forces and their Eritrean allies since November 2020.
The BBC could not reach either Eritrean or Tigrayan forces for comment.
Both the Ethiopian government and Tigrayan forces have said that they are preparing for another round of war.
TPLF chairman Debretsion Gebremichael last week said that "the people of Tigray will bear the burden of ensuring their survival" if the international community couldn't ensure that desperately needed food aid was sent to the region.
"Seven million Tigrayans are facing semi-starvation. Of course, we will not all perish in 60 days, but there are limits to society's endurance," he wrote to the UN.
On Saturday, Ethiopian Prime Minister Abiy Ahmed said that the army was ready to "defend like a lion, and attack like a wolf".
Meanwhile, the prime minister's office has referred to the disputed Western Tigray region as being part of the Amhara Region. It is officiaily part of Tigray but has been under the control of Amhara forces since the conflict started.