People are dying in large numbers in a refugee camp in South Sudan, the Medecins Sans Frontieres has warned.
The medical charity says as many as four young children die at the Batil camp everyday - twice the established emergency threshold.
The rainy season makes it impossible to bring food in by road, and the only way to deliver aid is by air.
Some 120,000 refugees have fled to camps in South Sudan from Sudan following fighting north of the border.
"What we are seeing here in this camp in nothing short of a humanitarian catastrophe," MSF's medical co-ordinator Helen Patterson said.
The majority of those who have died in the camp are children under five, and the MSF says that diarrhoea seems to be the biggest cause.
It adds that malnutrition is a contributing factor, calling for urgent help.
One man, Ibrahim, says his mother died after reaching Batil.
Osman, another refugee, says he has already lost his nephew, and is worried that the baby boy's father will soon die too.
Refugees - many of whom walked to weeks to get to camps - say they were forced from their homes in South Korofan and Blue Nile State by ground and air attacks by the military.
Officials in Khartoum deny that civilians are being targeted.