Aid agencies say people forced from their homes by the fighting in South Sudan are in desperate need of help and shelter.
An estimated 75,000 people are camped on the banks of the Nile after crossing by boat to escape the town of Bor.
Bishop Ruben Akurdit Ngong, who fled the fighting on Sunday and is now in the capital Juba,
described the town as a "war zone" with dead bodies ''everywhere".
''There is no clean drinking water. Five boreholes - it's just not enough," David Nash of Medecins Sans Frontieres told the BBC.
"People are drinking water straight out of the river Nile. It's muddy, it's not good. And there are no latrines, so open defecation is happening. Conditions for an outbreak of watery diarrhoea are perfect."
A state of emergency was declared by President Salva Kiir on Wednesday in two states, Unity and Jonglei.
A power struggle began last month between supporters of President Kiir and those of his former deputy Riek Machar, which the BBC reports has now taken on the overtones of an ethnic conflict.
