Presidents Omar Hassan al-Bashir of the Republic of Sudan and Silva Kiir of the Republic of South Sudan at a meeting during the African Union Summit in Addis Ababa, Ethiopia on July 14, 2012. The two Sudans have agreed to further talks., a photo by Pan-African News Wire File Photos on Flickr.
23 September 2012
Last updated at 16:23 ET
Rivals start summit on Sudan oil and border plan
Talks between the two countries over the border have been difficult
The leaders of Sudan and South Sudan have begun direct talks in the Ethiopian capital Addis Ababa on a deal to overcome a bitter border dispute.
UN Secretary General Ban Ki-moon has urged Sudanese President Omar al-Bashir and his South Sudanese counterpart Salva Kiir to reach a deal.
The two countries fought each other on their disputed border in April, sparking fears of a return to war.
The UN has threatened sanctions if Sunday's talks do not produce a deal.
Mr Kiir told South Sudanese state media he hopes for a "celebration" after meeting Mr Bashir.
The Security Council has called for an urgent agreement on a demilitarised border zone.
Mr Ban called for "co-operation and mutual development", and the US said Sudan should agree to an African Union border plan already accepted by South Sudan.
Last month, the two countries agreed to re-open their land border after a closure lasting more than a year.
However, the border remains unmarked.
At independence in July 2011, the South gained two-thirds of the region's oil while Sudan retained the processing and export facilities.
In January, the South shut down oil production, accusing Sudan of stealing its oil, and the two countries' economies have been damaged as a result.
Negotiating teams say they made progress on several of the outstanding issues before the heads of state arrived, but several blockages remain, the BBC's James Copnall reports from Addis Ababa.
The hope is that some degree of progress would encourage South Sudan to restart oil production, providing much needed revenue to both countries, he says.
Foreign diplomats are cautiously optimistic and exerting gentle pressure on both sides, our correspondent adds.
Delegations from the two states have already been in Addis Ababa for talks since 4 September.
Atif Keir, a spokesman for South Sudan's delegation, said talks had continued late into Saturday evening.
However, an ambassador quoted by Reuters news agency said it was unlikely the two leaders would agree on borders on Sunday although a deal on resuming oil exports was possible.
"The borders will take forever," the unnamed diplomat said. "They will exchange maps with experts, visit each other, go maybe into arbitration."
South Sudan, where people chiefly follow the Christian faith or traditional indigenous religions, fought for decades with mainly Muslim Sudan.