Somalia's militant group al-Shabab says it will use guerilla tactics in the capital, Mogadishu, where a massive new shipment of foreign aid has just arrived in the famine-hit country.

In an interview aired on London's Somali Channel on Friday, al-Shabab leader Sheik Hassan Dahir Aweys said the group will use the new strategy because it cannot match the military power of pro-government forces.

The Somali government, backed by African Union forces, pushed out the al-Qaida-linked rebels on August 6 to make way for foreign aid to help drought and famine victims.

Al-Shabab has banned most foreign groups from operating in areas under its control.

The World Food Program says it completed the second of three major airlifts into Mogadishu on Friday. It delivered 32-metric tons of shelter and other supplies.

Separately, the United Nations warns Somalia is facing a cholera epidemic as people migrate in search of food and water. The world body blames the outbreak on unsanitary conditions and a lack of clean water, particularly in refugee camps and informal settlements that have sprung up.

Dr. Michel Yao, a public health advisor for the World Health Organization, says cholera cases among the refugee population in Mogadishu have risen sharply.

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.

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.