The United Nation's humanitarian agency says Sudan's government is allowing it limited access to a volatile border town in the country's south but says many parts of the city are still off limits.

The United Nations Office for the Coordination of Humanitarian Affairs says its aid workers have been able to enter Kadugli, the capital of the tense Southern Kordofan state. However, the agency says the workers only have access to the parts of the city where aid groups have offices and says they are still not able to distribute aid to people in the city.

The United Nations said all agency offices in Kadugli have been looted.

Earlier this week, a senior U.N. human rights official said clashes along Sudan's north-south border have caused “utter devastation” in the region.

Weeks of fighting in Southern Kordofan and the neighboring Abyei region has led to a mass exodus of people and raised fears of a new Sudanese civil war.

Southern Sudan is set to declare independence on July 9, but northern and southern leaders have not agreed on their final border, nor on the future of oil-rich and fertile Abyei.

North and South Sudan fought a 21-year civil war that ended with a 2005 peace deal. South Sudan voted to split from the north in a referendum in January.