The UN is in a race against time to get food supplies to Sudanese refugees crossing the border into Chad before the rainy season begins, as neighbouring countries struggle to cope with the numbers of people fleeing the civil war.
More than 110,000 people are now estimated to have crossed into other countries as patchy ceasefires fail to stop deadly clashes between Sudanese army troops and a paramilitary rival that have killed hundreds and forced more than 330,000 from their homes.
