Border security talks between Sudan and South Sudan are deadlocked, the top southern negotiator said on Tuesday, Dec 18, raising the prospect of an impasse that could prolong a shutdown of oil exports and push both economies closer to collapse, Reuters reported.

The former civil war foes came close to all-out war in April after troops clashed along their shared border in the worst violence since South Sudan declared independence from Sudan last year.

They agreed in September to end hostilities, pull back troops and restart the transportation of southern oil through Sudanese pipelines. But South Sudan negotiator Pagan Amum told Reuters talks on how to put those promises into practice had now stalled.

"The talks now are deadlocked and, essentially, I see these talks as having collapsed because Sudan has taken a new strategic position opposing the development of cooperation between the two states," he said in an interview.

"I am not seeing any point of continuing these talks. I think it is now time for the leadership of South Sudan to refocus their attention," Amum added.

Defense ministers and other senior officials from both sides arrived in Addis Ababa at the weekend to hammer out another deal, and their talks were expected to end on Tuesday.

Amum said Khartoum's position meant resuming oil exports through Sudan was unlikely now.

"The only way out of this is to abandon all ideas about oil flowing through Sudan and build refineries inside South Sudan and build alternative pipelines to the Indian Ocean," Amum said.

The South had suggested building alternate pipeline in the past, but analysts have said such a scheme would take years to build and cost billions of dollars.

Sudan's Defense Minister Abdel Raheem Mohammed Hussein said the negotiations were ongoing, but declined to give further details.