Ethiopian rebel group The Ogaden National Liberation Front (ONLF) officer on thursday claimed their fighters had killed some 20 Ethiopian soldiers in the Ogaden region over the past week where the Ethiopian forces are cracking down on insurgents, spokesman said.
Abdullahi Arte also said that the rebels had also burnt 3 armed vehicles in the area of Fiiq.
They had been regrouping in the Lander area of southeast Ogaden.
"Around 20 colonial soldiers have been killed after regrouping in the Lander area," Arte said.
"Several hundred others, including seven top leaders and were also injured," he said, in a telephone teleconference for the local media.
Neither the claims by the rebels nor the army have been independently verified.
The army has stopped journalists and aid workers from entering the region, which borders lawless Somalia.
The Ethiopian army launched a crackdown on the region after ONLF rebels attacked a Chinese oil venture in April that left 77 people dead.
The barren Ogaden region, neighbouring lawless Somalia, has long been extremely poor, but the discovery of gas and oil has brought new hopes of wealth as well as new causes of conflict.
It is about the same size as Britain with a population of about four million.
Ethiopia accuses arch-foe Eritrea of supporting Ogaden separatists, which the authorities in Asmara have denied.
Formed in 1984, the ONLF is fighting for the independence of ethnic Somalis in Ogaden, whom they say have been marginalised by Addis Ababa.