The United Nations says Somalia is facing a cholera epidemic as people in the famine-hit country migrate in search of food and water.

Dr. Michel Yao, a public health advisor for the World Health Organization, says cholera cases among the refugee population in the capital, Mogadishu have risen sharply. He blames the outbreak on unsanitary living conditions and a lack of clean water.

Speaking from Geneva, Yao told reporters Friday that more than 181 children under the age of five have died this year in Mogadishu's Banadir hospital alone.

Officials say so far this year, the organization has recorded nearly 4,300 cases of acute watery diarrhea, up to three times more cases than a year ago.

The U.N. estimates that 100,000 Somalis have fled to Mogadishu in recent months, particularly from famine-hit areas in the south.

Most of the famine zones are controlled by al-Qaida-linked al-Shabab militants, who have banned most foreign aid groups.

The United Nations estimates more than 12 million people in the drought-stricken Horn of Africa need immediate aid.

The region is experiencing the worst drought in more than six decades.