Convoys of minibuses are making the trip back and forth from the Somali border to refugee camps in Ethiopia, as people flee the worst famine in years.
UNHCR Head of Emergency Operations Jo Hegenauer said the death rates in the camps are 'extremely high and they worry everyone'.
Figures are as high as ten per day in some camps.
'If we don't respond quikly to this..I think we're going to have serious long term problems', he said.
The UN warned last week that almost 10 million people in the Horn of Africa are facing a humanitarian emergency as the region struggles to deal with its worst drought for 60 years.
The BBC's Mike Woolridge reports from Kobe camp in Ethiopia.
