Sudan and South Sudan’s leaders negotiated positions Sunday as international pressure mounts to end long-running disputes that have brought the former civil war foes to the brink of renewed conflict. The rival delegations have held drawn-out talks that began several months before South Sudan split in July 2011 from what was Africa’s biggest nation, following a landslide independence vote after decades of war. Among issues on the table are understood to be ownership of contested regions along their frontier — especially the flashpoint Abyei region — and the setting up of a demilitarised border zone after bloody clashes. The buffer zone would also potentially cut support for rebel forces in Sudan’s Southern Kordofan and Blue Nile regions, where Sudan accuses Juba of supplying former civil war comrades whom Khartoum now seeks to wipe out. Multiple rounds of talks have failed to find solutions, but both sides have said they are now optimistic, given the looming threat of UN Security Council sanctions and the fact the two presidents were due to meet. “We are still facing difficulties... but we are hopeful we can reach a deal,” said Atif Kiir, spokesman for South Sudan’s delegation to the African Union mediated talks in the Ethiopian capital. “The summit is to reach a comprehensive agreement between the two countries, so let us hope,” his Sudanese counterpart Badr Al Din Abdullah told reporters late Saturday, when negotiations stretched into the night. A UN deadline passed Saturday for Sudanese President Omar Al Bashir and his Southern counterpart Salva Kiir to settle the raft of issues unresolved when the South became the world’s newest nation last year. The deadline was set after brutal border clashes broke out in March, when Southern troops and tanks briefly wrested the valuable Heglig oil field from Khartoum’s control, and Sudan launched bombing raids in response. UN leader Ban Ki-moon has called on the leaders to tackle their remaining differences, “so that their summit concludes with a success that marks an end to the era of conflict.” Bashir, who arrived Sunday morning, first held talks with Ethiopian Prime Minister Hailemariam Desalegn, before heading to meet with his delegation. “The proposals are on the table, they are going to deal with the issues,” Ethiopian State Minister of Foreign Affairs Berhane Gebre-Christos told reporters. “We are hopeful of a deal.” A meeting with his counterpart Kiir is expected late Sunday evening, according to South Sudanese officials, with negotiators busy shuttling between the teams to narrow positions. “A short delay means nothing ... both sides are working hard to settle demands ahead of the meeting,” a diplomat said. ‘Time to rebuild’ For once, the mood in these long-running talks appeared largely positive, with both Khartoum and Juba apparently keen to end conflict and a stalemate over stalled oil production that is crippling both their economies. Chief mediator Thabo Mbeki, the former South Africa president, was seen shuttling between multiple delegations addressing issues of security, border demarcation, oil and finance. “There does seem a genuine move towards finding a broad solution, even if technical issues and details will certainly need fixing in future meetings,” a Western diplomat said. “We are not going to go back to fighting each other, we know the cost of that after 50 years of war,” said the South’s spokesman, Kiir. “It is time to rebuild our lives, to rebuild our nation.” But delegates are also acutely aware that both sides have signed multiple deals in the past, including agreement on demilitarised border zones that were never fixed, and non-aggression pacts scuppered by subsequent clashes. “Reaching a deal is one thing, implementation is another,” the Southern spokesman added. A comprehensive deal — as opposed to another stepping stone agreement — would have to include settlement on Abyei, a Lebanon-sized frontier area claimed by both sides and currently controlled by Ethiopian peacekeepers. But amidst the diplomatic optimism, there seemed Sunday little chance of a breakthrough to solve the growing humanitarian crises in Sudan’s civil war states of Southern Kordofan and Blue Nile.