Mbeki arrives in Sudan for crisis talks
Former South African President Thabo Mbeki has arrived in Khartoum to attempt to restart negotiations between Sudan and South Sudan.
The African Union's mediator is due to meet Sudan's President Omar al-Bashir to try to set out an agenda and timetable for talks.
Heavy fighting between Sudan and the new nation of South Sudan brought them to the verge of war last month.
The UN has threatened sanctions if the situation is not resolved swiftly.
According to a United Nations Security Council resolution, talks aimed at resolving the dispute should have started this week.
South Sudan - which only seceded from its northern neighbour last year - said it is prepared to talk without preconditions, while Sudan has said it wants negotiations to focus on security.
The latest crisis began in April when South Sudanese troops took over the Heglig oilfield, which is one of Sudan's biggest sources of revenue.
South Sudan claims the oilfield falls within its territory, but the exact location of the border still had not been decided when the South became an independent nation last July, taking most of the united country's oil with it.
Under international pressure, South Sudan later withdrew from Heglig.
At a meeting of the Security Council on Thursday, members adopted a resolution demanding the finalisation of a jointly-run administration and police force for the disputed border region of Abyei near Heglig.
The United Nations has said that unless the border question and other issues are resolved within the next three months, it will consider imposing sanctions.
For that, the two countries need to sit round the negotiating table, but the latest round of fighting has derailed talks.
The two countries are also still to agree on what rights their citizens should have in the other - some 500,000 Southerners are now foreigners in Sudan, along with some 80,000 northerners in the South.
A deadline for a group of some 15,000 Southerners to leave Sudan expires on Sunday - the first group has already started flying to the South, a country some of them had never visited before.
In addition to meeting President Bashir and other senior officials in Khartoum, Mr Mbeki is expected to travel to the South's capital Juba to try to get the two sides to agree to new talks.