The UN has been assured that food will be allowed into Ethiopia's Ogaden region and there will be no famine, the UN's emergency relief chief says.
For months, outside agencies were denied access to Ogaden
"I received very strong assurances from the prime minister downwards," he told the BBC after a visit to the area.
The south-eastern region has been off limits to aid agencies after rebel attacks and a counter-insurgency.
An Ogaden rebel group spokesman has told the BBC that residents caught in the middle are already starving.
Earlier this year, Ethiopia expelled the Red Cross from the Somali region - known as the Ogaden - following activities by the rebel group the Ogaden National Liberation Front (ONLF).
The group attacked a Chinese run oil field in April, killing 74 people.
Normal food supplies - whether from aid agencies or commercial suppliers - have not been reaching most of the people for several months.
The UN humanitarian affairs co-ordinator Sir John Holmes made his comments after a visit to the Ogaden and said he felt a humanitarian crisis could be averted.
"Clearly, there are issues already about the availability and the price of food, and the ability of the population to cope with the situation they're in. I didn't get the impression that we're in a catastrophic humanitarian situation now," he told the BBC from the Ethiopian capital, Addis Ababa.
He said he had received assurances that Ethiopian officials "will do everything that had to be done to make sure there was no famine in the area and that all these needs will be addressed".
"They could not have been clearer about that. We will work with them very closely to try to make sure that there will be no kind of famine that we have been talking about and that all these needs are addressed," he said.
Only if measures - such as allowing commercial traffic into the region - were not taken then in a few months time "we could be in a very serious humanitarian crisis situation", he said.
ONLF spokesman Abdulrahman Mahdi told the BBC's Focus on Africa programme his organisation welcomed Sir John's visit to the Ogaden but thought it had been "stage-managed".
"Ethiopia is very good at stage-managing situations on the ground to show him food had been distributed on the day he arrived - but I can assure you that at the moment it doesn't reflect the reality for the Ogaden," he said.
"99% of the people of the Ogaden are starving in the countryside."
The picture given to the UN humanitarian co-ordinator had been "glossed over", he said.