South Sudan conflict: UN denies camp 'indifference'
The UN has rejected criticism that it is showing "shocking indifference" towards some 21,000 people sheltering at one of its compounds in South Sudan's capital, Juba.
On Wednesday, medical charity MSF said the group was "living in flood water contaminated with faecal matter".
The UN was doing its best to improve conditions, a UN official said.
The group sought refuge at the compound after fighting broke out between government and rebels in December.
The UN has around 8,000 peacekeepers in South Sudan, the world's newest state.
More than one million people have fled their homes since the conflict began, while nearly one-third of South Sudan's population, about 3.7 million people, are at severe risk of starvation, according to the UN.
Toby Lanzer, the UN assistant secretary general in Juba, told the BBC the "very pointed attack" by Medecins Sans Frontieres was "unnecessary and unhelpful".
"This is the base which was not created or planned for such an influx of people who need to stay alive and stay alive they have," he said.
"We've provided water, sanitation and I should mention the entire base is on the edge of the Nile.
"Everybody knew that flooding could be an issue, that there would be a public health risk and actually we welcome the MSF into the base, and would continue to do so, to work with us to address the public health concerns," he added.
Diarrhoeal diseases, respiratory infections and skin diseases had broken out among displaced people at the compound, MSF said in a statement.
About 150 latrines had collapsed, mixing with floodwater at the Tromping base, it said.
"People are living in natural drainage channels as there is no other space and there are 65 people per latrine," said Carolina Lopez, MSF's emergency co-ordinator.
The violence which caused the displaced people to flee erupted on 15 December between pro-government forces loyal to President Salva Kiir and soldiers backing Riek Machar, his former vice-president.
President Kiir accused Mr Machar of plotting a coup, an allegation he denied.
A ceasefire was agreed between the two sides towards the end of January, but they have accused each other of violating it.
South Sudan seceded from Sudan in 2011 after a long and bloody conflict, to become the world's newest nation.