More than 20,000 people have crossed into Kenya to escape the fighting, the Kenyan Red Cross says.
People were continuing to cross the border although Ethiopian government forces had intervened to stop the fighting.
The clashes, in the Moyale area, are thought to have been sparked by a simmering dispute over land rights.
Fighting involving the Borana and Garri communities is said to have started mid-week, and to have continued until Friday.
Local reports speak of armed militias taking up positions in outlying villages on Wednesday, with the fighting spreading to Moyale town, on the Ethiopia-Kenya border, on Thursday.
Many of those who fled across the border into the Kenyan side of Moyale are having to sleep out in the open.
The Red Cross says it is providing those who have been displaced with food, water and tarpaulins.
The US House Ethics Committee has voted to release its report on former Republican Representative…
ABC News has agreed to pay $15 million to President-elect Donald Trump to settle a…
South Korea’s parliament has voted to impeach President Yoon Suk Yeol over his failed attempt…
Israeli war planes have carried out more than 100 air strikes in Syria on December…
President-elect Donald Trump has threatened to impose 100% tariffs on the BRICS countries if they…
Syrian troops have withdrawn from the city of Aleppo following an offensive by rebels opposed…