by Natalie Duval and Biodun Iginla, BBC News

The UN is extending a mass vaccination programme against measles

Death rates are at "alarming levels" at a refugee camp in Ethiopia, where on average 10 children aged under five die each day, the UN has said.

It said high child mortality levels had been compounded by a suspected measles outbreak at the 25,000-capacity Kobe camp. Children are now vaccinated.

Most of the refugees have fled conflict and famine in rural parts of Somalia.

Some 12 million people across East Africa have been affected by the region's worst drought for 60 years.

Kobe is part of south-east Ethiopia's Dollo-Ado complex of refugee camps, which houses about 121,000 people in total and continues to receive 200 to 250 new arrivals each day.

Measles is being blamed for 11 deaths, with 150 suspected cases recorded across the complex's four sites.

Adrian Edwards, spokesman for the UN High Commissioner for Refugees (UNHCR), said: "Death rates have reached alarming levels among new arrivals.

"The combination of disease and malnutrition is what has caused similar death rates in previous famine crises in the region."

The agency said it had completed a mass vaccination campaign for children aged six months to 15 at Kobe and will now continue the programme at the other sites.

Thousands of Somalis have been fleeing to neighbouring countries each week. The UN has declared five famine zones in Somalia, where an estimated 3.2 million people are in need of immediate life-saving assistance.

Delivering aid has proven difficult because most of the famine-affected areas are controlled by the Islamist insurgent group, al-Shabab, which has been reluctant to co-operate with international agencies.

The UN said earlier this month that aid was only reaching 20% of the Somalis who needed it.