Sudan's President Omar al-Bashir arrives for talks with his South Sudanese counterpart Salva Kiir.
"There is agreement on some areas," said South Sudan delegation spokesperson Atif Kiir, while his Sudanese counterpart Badr el-din Abdullah Badr spoke of "progress on many issues," with both saying a deal would be inked on Thursday.
The partial agreement was reached after four days of marathon negotiations between the former civil war foes, President Omar al-Bashir of Sudan and his Southern counterpart Salva Kiir, in Ethiopia's capital.
While few details were released, both said a demilitarised border buffer zone – where troops must withdraw 10km from the de facto line of control along the undemarcated frontier – had been agreed.
Economic agreements were also reportedly reached, building on an oil deal last month to ensure South Sudan's stalled production would restart, after a stoppage that had damaged the economies of both nations.
But they did not reach agreement on the contested flashpoint Abyei region or on a series of border zones claimed by both sides.
"The two countries failed to reach an agreement on two issues – that of Abyei … [and] the second issue is that of the border," Kiir told reporters after the talks ended late on Wednesday.
"The two countries have agreed to have another round of talks … mainly on the issue of the border, on the disputed and unclaimed areas," he added.
His counterpart Abdullah said optimistically that the issues would be addressed in the future.
"We have overcome many differences … but here are some differences on Abyei," he said, adding also that resolving border areas claimed by both sides "is going take time".
No dates were given for a potential further round of talks.
Amid international pressure on both sides to reach a deal – after missing a UN Security Council deadline to settle by last Saturday – their teams spent days trying to narrow positions as mediators shuttled between them.
The protracted talks under African Union mediation began in the Ethiopian capital several months before South Sudan split in July 2011 from what was Africa's biggest nation, following an independence vote after decades of war. – Sapa-AFP