Sudan and South Sudan reached agreements on a demilitarised border zone and oil production but made limited progress on contested areas, their officials said late Wednesday.
"There is agreement on some areas," said South Sudan delegation spokesman 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 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 10 kilometres (six miles) from the de facto line of control along the undemarcated frontier -- had been agreed.
The buffer zone would also potentially cut support for rebel forces in Sudan's Southern Kordofan and Blue Nile regions that Khartoum accuses Juba of backing, just as the South accuses Sudan of arming rebels in its territory.
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 has damaged the economies of both nations.
The talks -- originally billed as a one-day summit -- had been hoped to provide a comprehensive solution to the festering disputes that took the rivals to the brink of war earlier this year.
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 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.
It was also not clear if all negotiations had been entirely settled, or whether talks could still continue Thursday.
"Only the final touches remain," Abdullah added.
Amid international pressure on both sides to reach a deal -- after missing a UN Security Council deadline to settle by Saturday -- their teams spent days trying to narrow positions as mediators shuttled between them.
The UN set a deadline for a deal after border fighting broke out in March, when Southern troops briefly wrested the valuable Heglig oil field from Khartoum's control, and Sudan launched bombing raids in response.
The protracted talks under African Union mediation began in Addis Ababa several months before South Sudan split in July 2011 from what was Africa's biggest nation, following an independence vote after decades of war.