By Ulf Laessing
ADDIS ABABA (Reuters) - Sudan and South Sudan reached a border security agreement on Wednesday that will allow the resumption of southern oil exports through the north, spokesmen for both sides said.
The leaders of the African neighbours reached a breakthrough after four days of talks in the Ethiopian capital, Addis Ababa, both delegations said.
Sudanese President Omar Hassan al-Bashir and his South Sudanese counterpart Salva Kiir had met six times since Sunday to iron out a pact key to reviving their economies after their armies came close to all-out war along a disputed frontier in April.
The African Union worked to broker the agreement and the U.N. Security Council had warned of sanctions against both states if no deal is done.
Ethiopia's government, hosting the talks, had arranged for a news conference on Wednesday afternoon, only to postpone it because of last-minute haggling after three weeks of negotiations between delegations.
It was hoped that the deal would provide for a demilitarised buffer zone along the border, according to diplomats and delegation sources.
The United Nations had set a September 22 deadline for a deal but informally extended it until the end of the Addis Ababa summit.
Last month the sides reached an interim deal to restart oil exports from the landlocked South through the north to Red Sea ports after the South shut down its wells in a row over transit fees.
While the security deal should provide both nations with the oil revenues needed to stave off economic collapse, they have yet to sort out several other conflicts left over from South Sudan's secession in July 2011.
They still need to agree on marking out their 1,800-km (1,200-mile) long common border, where there are at least five disputed sections. Their fate will probably have to be decided in future talks or through lengthy international arbitration.
Bashir and Kiir also discussed a solution to the disputed border region of Abyei, with plans for a referendum snagged on discord over who should be able to vote.
The two presidents are also expected to sign deals to boost cross-border trade and grant citizens of both nations residency in the other's country, ending uncertainty for South Sudanese living in Sudan.
The summit had originally been scheduled to take place in the South Sudanese capital Juba in April, but was cancelled after border fighting broke out and South Sudan briefly seized an oilfield vital to Sudan's economy.
Experts say restarting oil flows will take several months as the two export pipelines running through Sudan were filled with water to prevent them becoming blocked through "gelling". Some oil facilities were also damaged during the fighting.
South Sudan, where most people follow Christian and animist beliefs, seceded from the mainly Muslim north in July 2011 under a 2005 peace agreement that ended decades of civil war.
There was no sign of progress in indirect talks held in Addis Ababa between Sudan and the rebel Sudan People's Liberation Movement-North (SPLM-North), which is fighting the Sudanese army in two areas bordering South Sudan.
Diplomats say each country has given support to the other's rebels.
(Editing by Kevin Liffey)