A joint U.N.-African Union mission is going to Sudan's Southern Kordofan state Thursday in an effort to bring a halt to heavy fighting there.

VOA correspondent Peter Heinlein reports the mission was announced Wednesday in Addis Ababa, where north and south Sudanese officials are in talks aimed at easing tensions ahead of south Sudan's independence next month.

The mission to Southern Kordofan will be led by former South African president Thabo Mbeki, who heads a high-level AU panel on Sudan, and the U.N. secretary-general's special representative to Sudan, Haile Menkerios.

Earlier Wednesday, the U.N. humanitarian affairs office said fighting in Southern Kordofan between the northern army and local pro-southern fighters has displaced 60,000 people.

Meanwhile, a reported deal to ease tensions in Sudan's disputed Abyei region appears to be unraveling. VOA's Heinlein reports that according to a source involved in the talks, points which were previously settled have become unsettled, and the deal may be coming apart.

The African Union said Monday that north and south Sudan had agreed to “demilitarize” Abyei and allow Ethiopian peacekeepers into the area. Northern forces occupied Abyei last month, prompting tens of thousands of area residents to flee.

Late Tuesday, U.S. President Barack Obama called on the north Sudanese government to stop what he called its “campaign of intimidation” along the north-south border.

In an audio message, first aired on VOA, he also said the leaders of both north and south Sudan must live up to their responsibilities and agree to end the violence.

If they flout their obligations, Mr. Obama said they will face international pressure and isolation and will be held accountable for their actions.

Both north and south Sudan claim ownership of Abyei. The dispute there and in Southern Kordofan has raised fears of a renewed war in Sudan as the south prepares to declare independence July 9.

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