The United Nations has declared a famine in three more areas of southern Somalia, where a food crisis has claimed thousands of lives and left millions of people at risk.

Mark Bowden, UN humanitarian co-ordinator for Somalia, said Mogadishu, the Afgoye corridor outside the capital and the Middle Shabelle region are now in a state of famine.

The recent additions bring the number of famine zones in Somalia to five, and the UN cautioned that famine conditions could spread to all of southern Somalia within four to six weeks.

The UN relies on a five-level scale to gauge food security, ranging from "generally food secure" up to "famine/humanitarian catastrophe."

Local access restrictions, difficulties scaling up existing aid and funding gaps have slowed the humanitarian response, a report from the Famine Early Warning Systems Network said.

"As a result, famine is expected to spread across all regions of the south in the coming four to six weeks and is likely to persist until at least December 2011," the report said.

The UN office for the co-ordination of humanitarian affairs said about 1.25 million children in southern Somalia are in "urgent need of life-saving interventions" and some 640,000 more are acutely malnourished.

Augustine Mahiga, the special representative of the secretary general for Somalia, called on Somalis to try to work together to support peace and end the conflict that is contributing to the crisis.

He also called on local groups to give humanitarian groups unhindered access to communities in need, noting that insecurity has hampered aid efforts.

"I appeal to those who are able — Somalis and the international community alike — to give as much as they can during this Holy Month to feed the hungry, heal the sick and prevent the famine spreading further," Mahiga said.

So far, the famine designation has been limited to parts of Somalia, but many other East African communities are also dealing with a severe food crisis.

Drought conditions and conflict in Somalia have affected about 13 million people in the Horn of Africa, the World Food Program says.