The United Nations High Commissioner for Refugees, Antonio Guterres, says there are unprecedented levels of malnutrition among children fleeing Somalia to escape the severe drought in East Africa.
Oxfam, Save the Children and the Red Cross are all launching emergency appeals.
Rains have failed for the past three seasons, and aid agencies say more than 12 million people across large parts of Ethiopia, Somalia, and Kenya are facing dire shortages of food, shelter and health services.
The BBC's Ben Brown reports from the Dadaab refugee camp in Kenya.
