The head of the UN refugee agency has described the situation in drought-hit Somalia as the 'worst humanitarian disaster' in the world.

UNHCR head Antonio Guterres made the comments after meeting refugees in the world's largest refugee camp.

The Kenyan camp, Dadaab, is overflowing with tens of thousands of newly arrived refugees. They have been forced into the camp from the parched landscape in the region where Somalia, Ethiopia and Kenya meet.

The World Food Programme estimates that 10m people already need humanitarian aid.

The UN Children's Fund estimates that more than two million children are malnourished and in need of lifesaving action.

Mr Guterres appealed to the world to supply the 'massive support' needed by thousands of refugees showing up at that camp every week. More than 380,000 refugees now live there.

'The mortality rates we are witnessing are three times the level of emergency ceilings,' Mr Gutteres said. 'The level of malnutrition of the children coming in is 50%.

'That is enough to explain why a very high level of mortality is inevitable,' he said.

Dr Dejene Kebede, a health officer for UNHCR, said there were 58 deaths in camps in one week alone in June.

Most of the deaths take place at the registration office and transition facilities of the refugee camps in the southeastern Dollo region of Ethiopia, the health officer said.

Up to 2,000 Somali refugees are crossing the border into Ethiopia every day, UNHCR said.

Mr Guterres said the influx is overwhelming for UNHCR and other international and local aid organisations: 'Nothing can compare to what we have seen this month.'

'I believe Somalia represents the worst humanitarian disaster in the world,' he said.

Meanwhile, Ethiopia has said that it needs $398m to help millions of people in need of food aid due to the severe drought.

The figure marks a 40% rise in those needing food aid since April.

On Saturday, the UN emergency relief co-ordinator Valerie Amos called for long-term solutions to curb the effects of the severe drought in Ethiopia.

Ethiopia has also seen an influx of Somalis seeking relief from harsh drought and food scarcity.