NAIROBI, Kenya — The drought and famine in Somalia have killed more than 29,000 children under the age of 5, according to U.S. estimates, the first time such a precise death toll has been released related to the Horn of Africa crisis.

A child from southern Somalia takes food at a camp in Mogadishu, Somalia, Wednesday, Aug 3, 2011. Thousands of people have arrived in Mogadishu over the past two weeks seeking assistance and the number is increasing by the day. The worst drought in the Horn of Africa has sparked a severe food crisis and high malnutrition rates, with parts of Kenya and Somalia experiencing pre-famine conditions, the United Nations has said. More than 10 million people are now affected in drought-stricken areas of Djibouti, Ethiopia, Kenya, Somalia and Uganda and the situation is deteriorating, (AP Photo/Farah Abdi Warsameh) The United Nations has said previously that tens of thousands of people have died in the drought, the worst in Somalia in 60 years. The U.N. says 640,000 Somali children are acutely malnourished, a statistic that suggests the death toll of small children will rise.

Nancy Lindborg, an official with the U.S. government aid arm, told a congressional committee in Washington on Wednesday that the U.S. estimates that more than 29,000 children under the age of 5 have died in the last 90 days in southern Somalia. That number is based on nutrition and mortality surveys verified by the U.S. Centers for Disease Control and Prevention.

The U.N. on Wednesday declared three new regions in Somalia famine zones, bringing the total number to five. Out of a population of roughly 7.5 million, the U.N. says 3.2 million Somalis are in need of immediate lifesaving assistance.

Getting aid to Somalia has been made more difficult because al-Qaida-linked militants control much of the country's most desperate areas. Al-Shabab has denied that a famine is taking place, and won't give access to the World Food Program, the world's biggest provider of food aid.

Tens of thousands of refugees have fled south-central Somalia in hopes of finding food at camps in Ethiopia, Kenya and in Mogadishu, the Somali capital.

Hundreds of millions of dollars have been donated to fight the hunger crisis, but the U.N. says it needs hundreds of millions more.

How to help: http://www.interaction.org/crisis-list/interaction-members-respond-drought- crisis-horn-africa