RENK, South Sudan >> Tens of thousands of exhausted people are heading home to the world’s youngest country as they flee a brutal conflict in neighboring Sudan.

There’s a bottleneck of men, women and children camping near the dusty border of Sudan and South Sudan and the international community and the government are worried about a prolonged conflict.

Fighting between Sudan’s military and a rival militia killed at least 863 civilians in Sudan before a seven-day cease-fire began Monday night. Many in South Sudan are concerned about what could happen if the fighting next door continues.

Years of fighting between government and opposition forces in South Sudan killed almost 400,000 people and displaced millions until a peace agreement nearly five years ago. But the country has yet to deploy a unified military and create a permanent constitution. Large-scale clashes between the main parties have subsided, but there is still fighting in parts of the country.

— The Associated Press