The number of arrivals is projected to increase as the crisis continues, the UN's humanitarian affairs office (Ocha) has said.

Onward transportation of South Sudanese returnees and Sudanese refugees from transit sites remains a significant challenge due to the combination of poor road infrastructure and insecurity in some areas. There are also the additional logistical challenges posed by the onset of the rainy season, Ocha added.

“Many people who fled the conflict in Sudan are arriving across the border with nothing. Many reported that they were subjected to violence and exploitation, such as extortion and looting, as they fled to South Sudan. They need urgent support to reach safety and rebuild their lives,” Mr Van der Auweraert said.

The fighting between the Sudanese army and the paramilitary Rapid Support Forces (RSF), now in its third month, has displaced nearly three million people, according to estimates by humanitarian agencies.

The largest number of refugees have gone to Chad and Egypt.