Two years of Islamist insurgency have created one of the world's worst humanitarian crises in the Horn of Africa nation, with one million internal refugees, and others fleeing across borders to Ethiopia, Kenya and Djibouti.

"Increased numbers of Somali asylum-seekers fleeing insecurity continue to enter into (Ethiopia's) Somali Region since the beginning of 2009," the U.N. Office for the Office for the Coordination of Humanitarian Affairs (OCHA) said.

"They are crossing into Ethiopia at a rate of 150 a day," it added in a statement released this week.

Ethiopia recently withdrew troops from Somalia after a more than two-year intervention to counter Islamist groups.

"An estimated 10,000 asylum-seekers have arrived at the border town of Dolo Ado and the number of new arrivals is likely to further increase in the coming weeks," OCHA added.

Most of the refugees are women and children, it said.

Separately, the U.N. body said an estimated 12 million rural Ethiopians still needed food assistance this year. Soaring food prices, drought and conflict have all contributed to a dire humanitarian panorama across the Horn of Africa.

OCHA said $454.3 million was needed to help those 12 million Ethiopians for the first six month of 2009.