The Famine Early Warning Systems Network (Fewsnet) said areas of particular concern were in Ethiopia, Kenya and Somalia.

It said large-scale emergency assistance was urgently needed "to save lives and treat acute malnutrition" in the region.

It also stressed that the current humanitarian response was "inadequate".

In a statement, Fewsnet said the eastern Horn of Africa "has experienced two consecutive seasons of significantly below-average rainfall, resulting in one of the driest years since 1995".

It said that crops had failed and local cereal prices remained very high.

"This is the most severe food security emergency in the world today," the statement said.

In southern Ethiopia and some pastoral areas of Somalia, the agency said, "poor households are unable to access the basic food supplies needed for survival".

Fewsnet also said that recent nutrition surveys suggested that global acute malnutrition remained above 20 percent in the region, and more than seven million people needed humanitarian assistance.