U.N. aid agencies are warning that instability in the Horn of Africa could become more serious if donors do not respond quickly to aid appeals.

U.N. officials had a single message: aid is urgently needed to avert a major catastrophe in the Horn of Africa.

Musa Bungudu, the U.N. deputy humanitarian coordinator in Eritrea, said 70 percent of Eritrea's population of 2.3 million people is suffering from severe drought. Mr. Bungudu said young children are perhaps the most vulnerable.

"The gravity of this drought is already having a very, very serious impact on children under five years. We are seeing quite a number of malnourished children who are moving from moderate to severe and even dying," he said.

As bad as the situation is in Eritrea, U.N. aid officials said it is worse in Ethiopia, with three-quarters of the region's potential famine victims. They say the drought there has intensified competition over scarce water and pasture resources and led to the deaths of dozens of people.

Unlike Ethiopia and Eritrea, Somalia is not suffering from drought, but its situation is far from stable. It has been without a central government for 13 years. Max Gaylord is the U.N. resident coordinator for Somalia. He says if the needs of Ethiopia and Eritrea are not met, this will inevitably have an effect on Somalia.

"The danger for Somalia is spillover. So, already, livestock and whole families are trickling across into Somalia. If the drought, particularly in Ethiopia and also Eritrea, if it is not addressed at home, then you are going to find enormous pressure on the very fragile pastures and water sources of Somalia itself," Mr. Gaylord said.

The aid agencies say the message they are sending to donors is that a continued lack of response to their appeals will likely create more problems. And fixing those new problems, they say, will be far more expensive than if the problems are addressed now.