Fierce fighting at the border between Sudan and South Sudan is worsening an already grim humanitarian situation there, aid workers said yesterday, with a surge of refugees arriving in over-stretched camps.

In South Sudan’s Yida refugee camp – just one of several strung out along the volatile border – around 400 refugees are arriving every day, up from an average of 50 a day last week, the International Rescue Committee (IRC) aid agency said.

Those refugees are fleeing civil war and hunger in the Nuba mountains of Sudan’s Southern Kordofan state, an area close to where Sudan and South Sudan’s rival armies have been fighting in clashes that began last month.

There has been a “wave of refugees reaching the camp in crowded trucks and on foot,” IRC aid worker Elizabeth Pender said from Yida refugee camp, some 25 kilometres south of the border with Sudan.

Sudanese warplanes have launched a series of bombing raids along disputed border areas in the South’s Unity State, with fighting escalating last week after Southern troops seized the Heglig oil field from Khartoum’s army.

“We’re preparing for thousands more arrivals,” Ms Pender said, adding that those arriving said they were fleeing not only conflict but also growing hunger.