The UN humanitarian chief says nearly 17 million people in the Horn of Africa urgently need food, up from nine million in early 2008.
John Holmes said crippling drought, soaring food prices and conflict in some countries have created a humanitarian emergency in the region.
He told reporters on Friday that the humanitarian crisis hasn't yet escalated to a famine. But he warned that if donors don't provide $US716 million ($A891 million) very quickly the Horn could return to the famine situations of the 1980s and the 1990s.