The International Committee of the Red Cross (ICRC) has pulled out from Ethiopia's restive Ogaden region following a government order, but still hopes to return, a spokeswoman said on Thursday.

Authorities in Ethiopia's Somali regional state last week gave the Swiss-based humanitarian agency seven days' notice to leave, accusing it of consorting with rebels, an accusation it has rejected.

"We have left the Somali region, our two offices there are closed," ICRC spokeswoman Anna Schaaf said in Geneva.

Its 10 expatriate staff arrived in the capital Addis Ababa on Monday by road and remain on standby, she said.

"We are determined to have a good dialogue with authorities to see if we can return. We don't know what will become of the people we were assisting, there will be a hole," Schaaf said.

The expulsion shocked other humanitarian groups working in the desolate Ogaden area bordering Somalia, where a guerrilla group has accused the Ethiopian authorities of blockading food relief, choking commercial trade and risking "man-made famine".

The ICRC, which has said it performed its aid work "impartially and on strictly humanitarian grounds", carried out a variety of relief projects during its 12 years there.

Until the eviction, it provided medical supplies to hospitals and health care centres, trained livestock owners, carried out water and sanitation projects, and visited detention centres to evaluate conditions and treatment of prisoners.

On Wednesday, an Ethiopian rebel group, the separatist Ogaden National Liberation Front accused government troops of having killed two local aid workers in Ogaden on July 29.

The dry region, populated largely by nomadic camel herders, is effectively off-limits to most human rights workers and journalists.