The United Nations says the number of Somali refugees in the Horn of Africa has topped 860,000, many of them forced out by the ongoing drought and famine.

The U.N. refugee agency says another 1.5 million Somalis are internally displaced, mostly in Somalia's south-central region.

A report issued Wednesday says many Somalis fled their homes after the last of their livestock died, depriving them of income and food.

The agency says that since January, 125,000 Somalis have fled to Kenya, and another 76,000 to Ethiopia. Earlier Somali refugees were largely forced out by fighting between government forces and insurgents.

Somalia is at the center of the worst drought to hit the Horn of Africa in 60 years. The United Nations says more than 12 million people in the region are in need of food aid.

The U.N. recently declared a famine in two parts of southern Somalia, and has warned that famine conditions are likely to spread to other areas in the next four to eight weeks.

On Tuesday, British relief agency Oxfam said governments and donors need to fulfill their pledges of aid more quickly.

The U.N. refugee agency says large numbers of Somali children are malnourished, and the under-five mortality rate at refugee camps in Kenya is on the rise.