Government troops have executed civilians and conducted ethnic cleansing in Ethiopia's Somali Region, a rebel group said on Friday.

The Ogaden National Liberation Front (ONLF) said the bodies of a civil servant and a businessman were found dead in Kebridehar in eastern Ethiopia on January 17, a day after they and 17 other people were rounded up by security officials.

The government rejected the allegations.

Government spokesman Shimelis Kemal told Reuters a small gunfight had erupted between local police and ONLF fighters in Kebridehar on January 10 after ONLF members killed a civilian.

The Ethiopian army was not even involved, and this cannot be considered as ethnic cleansing. It was a measure taken by police against terrorist activities, Shimelis said.

The ONLF said in a statement Wires that were used to asphyxiate the victims were left wrapped around their necks for further terrifying the town's people.

The fate of the rest of the group was unknown, it added.

The ONLF is fighting for independence for the ethnic Somali-dominated Ogaden province. Ethiopia believes the Ogaden basin may contain 4 trillion cubic feet of gas reserves and major oil deposits, drawing interest from foreign firms.

The rebels said that in a second incident, government troops had beheaded a woman and injured 27 people while looting the town of Higlalay.

Since it is at the height of the dry season and both water and food are scarce, there is an urgent need of humanitarian aid for the victims, but the same army that is committing these crimes controls aid, the ONLF statement said.

It is not the first time the ONLF has accused government troops of atrocities in the region. It said in November last year that soldiers had tortured hundreds of civilians who had been displaced from their homes.

The allegations are impossible to verify because journalists and aid groups cannot move unhindered in the area.

Ethiopia signed a peace deal in October with one faction of the ONLF, though another faction called the deal irrelevant. The faction with which Addis Ababa sealed the accord says it represents 80 percent of ONLF fighters.